Hub Suspended Game Kill Affordance

Cargo.lock

@@ -1469,6 +1469,16 @@ version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
+[[package]]
+name = "pbxgen-dummy-boy"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "prometeu-bytecode",
+ "prometeu-hal",
+ "serde_json",
+]
+
 [[package]]
 name = "pbxgen-stress"
 version = "0.1.0"

Cargo.toml

@@ -8,6 +8,7 @@ members = [
   "crates/console/prometeu-vm",
   "crates/host/prometeu-host-desktop-winit",
   "crates/tools/prometeu-cli",
+  "crates/tools/pbxgen-dummy-boy",
   "crates/tools/pbxgen-stress",
   "crates/dev/prometeu-test-support",
   "crates/dev/prometeu-layer-tests",

crates/console/prometeu-drivers/src/asset.rs

@@ -1858,6 +1858,9 @@ impl AssetManager {
         self.glyph_slot_index.clear();
         self.sound_slots.write().unwrap().fill(None);
         self.scene_slots.write().unwrap().fill(None);
+        self.gfx_installer.clear_glyph_banks();
+        self.sound_installer.clear_sound_banks();
+        self.scene_installer.clear_scene_banks();
     }
 
     pub fn glyph_asset_slot_index(&self) -> GlyphAssetSlotIndex {
@@ -2668,6 +2671,51 @@ mod tests {
         assert_eq!(am.slot_info(SlotRef::scene(4)).asset_id, Some(2));
     }
 
+    #[test]
+    fn shutdown_clears_physical_memory_bank_slots() {
+        let banks = Arc::new(MemoryBanks::new());
+        let gfx_installer = Arc::clone(&banks) as Arc<dyn GlyphBankPoolInstaller>;
+        let sound_installer = Arc::clone(&banks) as Arc<dyn SoundBankPoolInstaller>;
+        let scene_installer = Arc::clone(&banks) as Arc<dyn SceneBankPoolInstaller>;
+
+        let glyph_data = test_glyph_asset_data();
+        let scene = test_scene();
+        let scene_data = encode_scene_payload(&scene);
+        let glyph_entry = test_glyph_asset_entry("preload_glyphs", 16, 16);
+        let scene_entry = test_scene_asset_entry("preload_scene", &scene_data, &scene);
+
+        let mut payload = Vec::new();
+        payload.extend_from_slice(&glyph_data);
+        payload.extend_from_slice(&scene_data);
+        let mut shifted_scene_entry = scene_entry;
+        shifted_scene_entry.offset = glyph_data.len() as u64;
+
+        let am = AssetManager::new(
+            vec![],
+            AssetsPayloadSource::empty(),
+            gfx_installer,
+            sound_installer,
+            scene_installer,
+        );
+        am.initialize_for_cartridge(
+            vec![glyph_entry, shifted_scene_entry],
+            vec![PreloadEntry { asset_id: 0, slot: 0 }, PreloadEntry { asset_id: 2, slot: 0 }],
+            AssetsPayloadSource::from_bytes(payload),
+        );
+
+        assert!(banks.glyph_bank_slot(0).is_some());
+        assert!(banks.scene_bank_slot(0).is_some());
+        assert_eq!(am.slot_info(SlotRef::gfx(0)).asset_id, Some(0));
+        assert_eq!(am.slot_info(SlotRef::scene(0)).asset_id, Some(2));
+
+        am.shutdown();
+
+        assert!(banks.glyph_bank_slot(0).is_none());
+        assert!(banks.scene_bank_slot(0).is_none());
+        assert_eq!(am.slot_info(SlotRef::gfx(0)).asset_id, None);
+        assert_eq!(am.slot_info(SlotRef::scene(0)).asset_id, None);
+    }
+
     #[test]
     fn test_load_returns_asset_not_found() {
         let banks = Arc::new(MemoryBanks::new());

crates/console/prometeu-drivers/src/memory_banks.rs

@@ -24,6 +24,8 @@ pub trait GlyphBankPoolAccess: Send + Sync {
 pub trait GlyphBankPoolInstaller: Send + Sync {
     /// Atomically swaps the resident GlyphBank in the specified slot.
     fn install_glyph_bank(&self, slot: usize, bank: Arc<GlyphBank>);
+    /// Clears all resident GlyphBank slots.
+    fn clear_glyph_banks(&self);
 }
 
 /// Non-generic interface for peripherals to access sound banks.
@@ -38,6 +40,8 @@ pub trait SoundBankPoolAccess: Send + Sync {
 pub trait SoundBankPoolInstaller: Send + Sync {
     /// Atomically swaps the resident SoundBank in the specified slot.
     fn install_sound_bank(&self, slot: usize, bank: Arc<SoundBank>);
+    /// Clears all resident SoundBank slots.
+    fn clear_sound_banks(&self);
 }
 
 /// Non-generic interface for peripherals to access scene banks.
@@ -52,6 +56,8 @@ pub trait SceneBankPoolAccess: Send + Sync {
 pub trait SceneBankPoolInstaller: Send + Sync {
     /// Atomically swaps the resident SceneBank in the specified slot.
     fn install_scene_bank(&self, slot: usize, bank: Arc<SceneBank>);
+    /// Clears all resident SceneBank slots.
+    fn clear_scene_banks(&self);
 }
 
 /// Centralized container for all hardware memory banks.
@@ -100,6 +106,10 @@ impl GlyphBankPoolInstaller for MemoryBanks {
             pool[slot] = Some(bank);
         }
     }
+
+    fn clear_glyph_banks(&self) {
+        self.glyph_bank_pool.write().unwrap().fill(None);
+    }
 }
 
 impl SoundBankPoolAccess for MemoryBanks {
@@ -120,6 +130,10 @@ impl SoundBankPoolInstaller for MemoryBanks {
             pool[slot] = Some(bank);
         }
     }
+
+    fn clear_sound_banks(&self) {
+        self.sound_bank_pool.write().unwrap().fill(None);
+    }
 }
 
 impl SceneBankPoolAccess for MemoryBanks {
@@ -140,6 +154,10 @@ impl SceneBankPoolInstaller for MemoryBanks {
             pool[slot] = Some(bank);
         }
     }
+
+    fn clear_scene_banks(&self) {
+        self.scene_bank_pool.write().unwrap().fill(None);
+    }
 }
 
 impl HalRenderResourceAccess for MemoryBanks {

crates/console/prometeu-firmware/src/firmware/firmware.rs

@@ -250,21 +250,24 @@ impl Firmware {
 mod tests {
     use super::*;
     use crate::firmware::firmware_state::HubHomeStep;
+    use crate::firmware::resident_game_termination::{self, ResidentGameTerminationOutcome};
     use prometeu_bytecode::assembler::assemble;
     use prometeu_bytecode::model::{BytecodeModule, FunctionMeta, SyscallDecl};
-    use prometeu_drivers::TestPlatform;
+    use prometeu_drivers::{GlyphBankPoolAccess, SceneBankPoolAccess, TestPlatform};
     use prometeu_hal::RuntimePlatform;
     use prometeu_hal::app_mode::AppMode;
+    use prometeu_hal::asset::{BankType, SlotRef};
     use prometeu_hal::cartridge::AssetsPayloadSource;
     use prometeu_hal::color::Color;
+    use prometeu_hal::log::{LogLevel, LogSource};
     use prometeu_hal::primitives::Rect;
     use prometeu_hal::syscalls::{Syscall, caps};
     use prometeu_system::process::ProcessState;
     use prometeu_system::task::{TaskId, TaskState};
     use prometeu_system::windows::WindowOwner;
     use prometeu_system::{
-        CrashReport, ForegroundOwner, GameLifecycleEventKind, ResidentGameState,
+        CrashReport, ForegroundOwner, GameLifecycleEventKind, HUB_SUSPENDED_GAME_KILL_CONTROL,
-        discover_games_root,
+        ResidentGameState, discover_games_root,
     };
     use std::fs;
     use std::path::PathBuf;
@@ -299,6 +302,18 @@ mod tests {
             title: &str,
             app_version: &str,
             with_program: bool,
+        ) -> PathBuf {
+            let program = with_program.then(halting_program);
+            self.add_game_with_program(name, app_id, title, app_version, program)
+        }
+
+        fn add_game_with_program(
+            &self,
+            name: &str,
+            app_id: u32,
+            title: &str,
+            app_version: &str,
+            program: Option<Vec<u8>>,
         ) -> PathBuf {
             let cart = self.path.join(name);
             fs::create_dir_all(&cart).expect("test cartridge should be created");
@@ -314,8 +329,8 @@ mod tests {
             );
             fs::write(cart.join("manifest.json"), manifest)
                 .expect("test manifest should be written");
-            if with_program {
+            if let Some(program) = program {
-                fs::write(cart.join("program.pbx"), halting_program())
+                fs::write(cart.join("program.pbx"), program)
                     .expect("test program should be written");
             }
             cart
@@ -346,6 +361,10 @@ mod tests {
         .serialize()
     }
 
+    fn repository_test_cartridges_root() -> PathBuf {
+        PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../../..").join("test-cartridges")
+    }
+
     fn invalid_game_cartridge() -> Cartridge {
         Cartridge {
             app_id: 7,
@@ -460,6 +479,12 @@ mod tests {
         windows.set_focus(id);
     }
 
+    fn front_buffer_pixel(platform: &TestPlatform, x: i32, y: i32) -> u32 {
+        const FRAMEBUFFER_WIDTH: usize = 480;
+        let index = x as usize + y as usize * FRAMEBUFFER_WIDTH;
+        platform.local_hardware().gfx.front_buffer()[index]
+    }
+
     #[test]
     fn load_cartridge_transitions_to_app_crashes_when_vm_init_fails() {
         let mut firmware = Firmware::new(None);
@@ -807,6 +832,433 @@ mod tests {
         }
     }
 
+    #[test]
+    fn repository_stress_to_dummy_boy_switch_is_end_to_end() {
+        let library = discover_games_root(repository_test_cartridges_root());
+        assert!(
+            library
+                .entries()
+                .iter()
+                .any(|entry| entry.app_id == 1 && entry.title == "Stress Console")
+        );
+        assert!(
+            library.entries().iter().any(|entry| entry.app_id == 2 && entry.title == "Dummy Boy")
+        );
+
+        let (mut firmware, mut platform) = hub_home_firmware();
+        firmware.hub.set_game_library(library);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&stress_click, &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_task = match &firmware.state {
+            FirmwareState::GameRunning(step) => step.task_id,
+            other => panic!("expected Stress GameRunning state, got {:?}", other),
+        };
+        assert_eq!(firmware.os.vm().current_app_id(), 1);
+        assert_eq!(firmware.os.vm().current_cartridge_title(), "Stress Console");
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            Some(100)
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            Some(1)
+        );
+
+        firmware.request_home_from_host();
+        firmware.tick(&InputSignals::default(), &mut platform);
+        let hub_ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(hub_ownership.app_mode, AppMode::Shell);
+        assert_eq!(hub_ownership.app_id, 0);
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            Some(100)
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            Some(1)
+        );
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+        let dummy_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 90, ..Default::default() };
+        firmware.tick(&dummy_click, &mut platform);
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            None
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            None
+        );
+        assert!(platform.local_hardware().memory_banks.glyph_bank_slot(0).is_none());
+        assert!(platform.local_hardware().memory_banks.scene_bank_slot(0).is_none());
+
+        assert_eq!(firmware.os.lifecycle().task_state(stress_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(stress_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(stress_task).map(|session| session.task_id),
+            None
+        );
+
+        let dummy_task = firmware
+            .os
+            .lifecycle()
+            .resident_game_task()
+            .expect("Dummy Boy should be resident after switch load");
+        assert_ne!(dummy_task, stress_task);
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(dummy_task).map(|session| {
+                (session.app_id, session.title.clone(), session.app_version.clone())
+            }),
+            Some((2, "Dummy Boy".to_string(), "0.1.0".to_string()))
+        );
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        match &firmware.state {
+            FirmwareState::GameRunning(step) => assert_eq!(step.task_id, dummy_task),
+            other => panic!("expected Dummy Boy GameRunning state, got {:?}", other),
+        }
+        assert_eq!(firmware.os.lifecycle().foreground_owner(), ForegroundOwner::Game(dummy_task));
+        assert_eq!(firmware.os.vm().current_app_id(), 2);
+        assert_eq!(firmware.os.vm().current_cartridge_title(), "Dummy Boy");
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let dummy_ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(dummy_ownership.app_mode, AppMode::Game);
+        assert_eq!(dummy_ownership.app_id, 2);
+
+        let front = platform.local_hardware().gfx.front_buffer();
+        let center = 240 + 135 * 480;
+        assert_eq!(front[center], Color::GREEN.raw());
+
+        firmware.request_home_from_host();
+        firmware.tick(&InputSignals::default(), &mut platform);
+        let hub_ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(hub_ownership.app_mode, AppMode::Shell);
+        assert_eq!(hub_ownership.app_id, 0);
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+        let stress_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&stress_click, &mut platform);
+
+        assert_eq!(firmware.os.lifecycle().task_state(dummy_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(dummy_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(dummy_task).map(|session| session.task_id),
+            None
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            Some(100)
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            Some(1)
+        );
+        assert!(platform.local_hardware().memory_banks.glyph_bank_slot(0).is_some());
+        assert!(platform.local_hardware().memory_banks.scene_bank_slot(0).is_some());
+
+        let second_stress_task = firmware
+            .os
+            .lifecycle()
+            .resident_game_task()
+            .expect("Stress should be resident after switching back");
+        assert_ne!(second_stress_task, stress_task);
+        assert_ne!(second_stress_task, dummy_task);
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        match &firmware.state {
+            FirmwareState::GameRunning(step) => assert_eq!(step.task_id, second_stress_task),
+            other => panic!("expected second Stress GameRunning state, got {:?}", other),
+        }
+        assert_eq!(firmware.os.vm().current_app_id(), 1);
+        assert_eq!(firmware.os.vm().current_cartridge_title(), "Stress Console");
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(stress_ownership.app_mode, AppMode::Game);
+        assert_eq!(stress_ownership.app_id, 1);
+    }
+
+    #[test]
+    fn resident_game_termination_noops_when_no_game_is_resident() {
+        let (mut firmware, mut platform) = hub_home_firmware();
+        let ownership_before = firmware.os.vm().active_render_ownership();
+
+        let outcome = resident_game_termination::terminate_resident_game(
+            &mut firmware.os,
+            &mut platform,
+            true,
+        )
+        .expect("no resident game termination should not fail");
+
+        assert_eq!(outcome, ResidentGameTerminationOutcome::NoResidentGame);
+        assert_eq!(firmware.os.vm().active_render_ownership(), ownership_before);
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), None);
+        assert!(
+            !firmware
+                .os
+                .recent_logs(16)
+                .iter()
+                .any(|event| event.msg.contains("Resident game killed from Hub"))
+        );
+    }
+
+    #[test]
+    fn resident_game_termination_closes_session_and_cleans_runtime_state() {
+        let library = discover_games_root(repository_test_cartridges_root());
+        let (mut firmware, mut platform) = hub_home_firmware();
+        firmware.hub.set_game_library(library);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&stress_click, &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_task = match &firmware.state {
+            FirmwareState::GameRunning(step) => step.task_id,
+            other => panic!("expected Stress GameRunning state, got {:?}", other),
+        };
+
+        firmware.request_home_from_host();
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        assert!(matches!(firmware.state, FirmwareState::HubHome(_)));
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), Some(stress_task));
+        assert!(firmware.game_lifecycle_audio_paused());
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            Some(100)
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            Some(1)
+        );
+        assert!(platform.local_hardware().memory_banks.glyph_bank_slot(0).is_some());
+        assert!(platform.local_hardware().memory_banks.scene_bank_slot(0).is_some());
+
+        let outcome = resident_game_termination::terminate_resident_game(
+            &mut firmware.os,
+            &mut platform,
+            true,
+        )
+        .expect("resident game termination should succeed");
+
+        assert_eq!(
+            outcome,
+            ResidentGameTerminationOutcome::Terminated {
+                task_id: stress_task,
+                title: "Stress Console".to_string()
+            }
+        );
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), None);
+        assert_eq!(firmware.os.lifecycle().task_state(stress_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(stress_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(stress_task).map(|session| session.task_id),
+            None
+        );
+        assert!(!firmware.game_lifecycle_audio_paused());
+
+        let ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(ownership.app_mode, AppMode::Shell);
+        assert_eq!(ownership.app_id, 0);
+        assert_eq!(platform.local_hardware().frame_composer.active_scene_id(), None);
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            None
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            None
+        );
+        assert!(platform.local_hardware().memory_banks.glyph_bank_slot(0).is_none());
+        assert!(platform.local_hardware().memory_banks.scene_bank_slot(0).is_none());
+
+        assert!(
+            firmware.os.recent_logs(32).iter().any(|event| {
+                event.level == LogLevel::Info
+                    && event.source == LogSource::Hub
+                    && event.msg == "Resident game killed from Hub: Stress Console"
+            }),
+            "manual Hub kill should emit an INFO log"
+        );
+    }
+
+    #[test]
+    fn hub_kill_control_click_terminates_resident_game_and_stays_home() {
+        let library = discover_games_root(repository_test_cartridges_root());
+        let (mut firmware, mut platform) = hub_home_firmware();
+        firmware.hub.set_game_library(library);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&stress_click, &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_task = match &firmware.state {
+            FirmwareState::GameRunning(step) => step.task_id,
+            other => panic!("expected Stress GameRunning state, got {:?}", other),
+        };
+
+        firmware.request_home_from_host();
+        firmware.tick(&InputSignals::default(), &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        assert!(matches!(firmware.state, FirmwareState::HubHome(_)));
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), Some(stress_task));
+
+        let kill_sample_x = HUB_SUSPENDED_GAME_KILL_CONTROL.x + 2;
+        let kill_sample_y = HUB_SUSPENDED_GAME_KILL_CONTROL.y + 2;
+        assert_eq!(
+            front_buffer_pixel(&platform, kill_sample_x, kill_sample_y),
+            Color::rgb(164, 32, 40).raw(),
+            "Hub should render the suspended-game kill control before click"
+        );
+
+        let kill_click = InputSignals {
+            f_signal: true,
+            x_pos: HUB_SUSPENDED_GAME_KILL_CONTROL.x,
+            y_pos: HUB_SUSPENDED_GAME_KILL_CONTROL.y,
+            ..Default::default()
+        };
+        firmware.tick(&kill_click, &mut platform);
+
+        assert!(matches!(firmware.state, FirmwareState::HubHome(_)));
+        assert_eq!(firmware.os.lifecycle().foreground_owner(), ForegroundOwner::Hub);
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), None);
+        assert_eq!(firmware.os.lifecycle().resident_game(), None);
+        assert_eq!(firmware.os.lifecycle().task_state(stress_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(stress_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(stress_task).map(|session| session.task_id),
+            None
+        );
+        assert!(!firmware.game_lifecycle_audio_paused());
+        assert!(!firmware.resume_resident_game_from_home());
+
+        let ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(ownership.app_mode, AppMode::Shell);
+        assert_eq!(ownership.app_id, 0);
+        assert_eq!(platform.local_hardware().frame_composer.active_scene_id(), None);
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::GLYPH, index: 0 }).asset_id,
+            None
+        );
+        assert_eq!(
+            platform.assets().slot_info(SlotRef { asset_type: BankType::SCENE, index: 0 }).asset_id,
+            None
+        );
+        assert!(platform.local_hardware().memory_banks.glyph_bank_slot(0).is_none());
+        assert!(platform.local_hardware().memory_banks.scene_bank_slot(0).is_none());
+        assert!(
+            firmware.os.recent_logs(32).iter().any(|event| {
+                event.level == LogLevel::Info
+                    && event.source == LogSource::Hub
+                    && event.msg == "Resident game killed from Hub: Stress Console"
+            }),
+            "Hub kill control should use the canonical manual kill log"
+        );
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+        assert_eq!(
+            front_buffer_pixel(&platform, kill_sample_x, kill_sample_y),
+            Color::rgb(12, 14, 22).raw(),
+            "Hub should stop rendering the kill control after the game is gone"
+        );
+    }
+
+    #[test]
+    fn failed_game_switch_returns_home_without_restoring_previous_game() {
+        let root = TestGameRoot::new();
+        root.add_game("stress", true);
+        root.add_game_with_program("zzz-broken", 43, "Zzz Broken", "1.0.0", Some(vec![0, 0, 0, 0]));
+
+        let (mut firmware, mut platform) = hub_home_firmware();
+        firmware.hub.set_game_library(discover_games_root(&root.path));
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let stress_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 90, ..Default::default() };
+        firmware.tick(&stress_click, &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let first_game_task = match &firmware.state {
+            FirmwareState::GameRunning(step) => step.task_id,
+            other => panic!("expected first GameRunning state, got {:?}", other),
+        };
+
+        firmware.request_home_from_host();
+        firmware.tick(&InputSignals::default(), &mut platform);
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        let broken_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&broken_click, &mut platform);
+
+        assert_eq!(firmware.os.lifecycle().task_state(first_game_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware
+                .os
+                .sessions()
+                .vm_session_for_task(first_game_task)
+                .map(|session| session.task_id),
+            None
+        );
+        let partial_task = firmware
+            .os
+            .lifecycle()
+            .resident_game_task()
+            .expect("failed target should be resident until recovery tick");
+        assert_ne!(partial_task, first_game_task);
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        assert!(matches!(firmware.state, FirmwareState::HubHome(_)));
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), None);
+        assert_eq!(firmware.os.lifecycle().task_state(first_game_task), Some(TaskState::Closed));
+        assert_eq!(firmware.os.lifecycle().task_state(partial_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(partial_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware.os.sessions().vm_session_for_task(partial_task).map(|session| session.task_id),
+            None
+        );
+        assert!(
+            firmware
+                .os
+                .recent_logs(16)
+                .iter()
+                .any(|event| event.msg.contains("Failed to switch to game Zzz Broken app_id 43"))
+        );
+    }
+
     #[test]
     fn invalid_games_root_candidate_is_omitted_from_home_launch_boundary() {
         let root = TestGameRoot::new();
@@ -989,6 +1441,8 @@ mod tests {
         };
         let tick_index_before_home = firmware.os.vm().tick_index();
         let render_ownership_before_home = firmware.os.vm().active_render_ownership();
+        assert_eq!(render_ownership_before_home.app_mode, AppMode::Game);
+        assert_eq!(render_ownership_before_home.app_id, 9);
 
         firmware.request_home_from_host();
 
@@ -1020,7 +1474,6 @@ mod tests {
         let render_ownership_after_home = firmware.os.vm().active_render_ownership();
         assert_eq!(render_ownership_after_home.app_mode, AppMode::Shell);
         assert_eq!(render_ownership_after_home.app_id, 0);
-        assert!(render_ownership_after_home.epoch > render_ownership_before_home.epoch);
         assert!(firmware.os.lifecycle().pending_game_lifecycle_events().is_empty());
         assert_eq!(
             firmware.os.vm().delivered_game_lifecycle_events().last().map(|event| event.kind),
@@ -1049,6 +1502,8 @@ mod tests {
         firmware.request_home_from_host();
         firmware.tick(&signals, &mut platform);
         let hub_ownership = firmware.os.vm().active_render_ownership();
+        assert_eq!(hub_ownership.app_mode, AppMode::Shell);
+        assert_eq!(hub_ownership.app_id, 0);
 
         assert!(firmware.resume_resident_game_from_home());
         assert!(matches!(firmware.state, FirmwareState::GameRunning(_)));
@@ -1061,7 +1516,6 @@ mod tests {
         let game_ownership = firmware.os.vm().active_render_ownership();
         assert_eq!(game_ownership.app_mode, AppMode::Game);
         assert_eq!(game_ownership.app_id, 9);
-        assert!(game_ownership.epoch > hub_ownership.epoch);
 
         let held_signals =
             InputSignals { up_signal: true, f_signal: true, x_pos: 72, y_pos: 90, ..signals };

crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs

@@ -2,6 +2,7 @@ use crate::firmware::firmware_state::{
     AppCrashesStep, FirmwareState, LoadCartridgeStep, ShellRunningStep,
 };
 use crate::firmware::prometeu_context::PrometeuContext;
+use crate::firmware::resident_game_termination;
 use prometeu_hal::app_mode::AppMode;
 use prometeu_hal::cartridge_loader::CartridgeLoader;
 use prometeu_hal::log::{LogLevel, LogSource};
@@ -69,7 +70,11 @@ impl HubHomeStep {
                                 return Some(FirmwareState::ResumeResidentGame);
                             }
 
-                            if let Err(error) = ctx.os.lifecycle().terminate_resident_game() {
+                            if let Err(error) = resident_game_termination::terminate_resident_game(
+                                ctx.os,
+                                ctx.platform,
+                                false,
+                            ) {
                                 ctx.os.log(
                                     LogLevel::Error,
                                     LogSource::Hub,
@@ -83,9 +88,9 @@ impl HubHomeStep {
                             }
                         }
 
-                        return Some(FirmwareState::LoadCartridge(LoadCartridgeStep::new(
+                        return Some(FirmwareState::LoadCartridge(
-                            cartridge,
+                            LoadCartridgeStep::new_game_switch(cartridge),
-                        )));
+                        ));
                     }
                     Err(error) => {
                         ctx.os.log(
@@ -101,6 +106,18 @@ impl HubHomeStep {
                     }
                 }
             }
+            Some(SystemProfileAction::KillResidentGame) => {
+                if let Err(error) =
+                    resident_game_termination::terminate_resident_game(ctx.os, ctx.platform, true)
+                {
+                    ctx.os.log(
+                        LogLevel::Error,
+                        LogSource::Hub,
+                        0,
+                        format!("Failed to kill resident game from Hub: {error:?}"),
+                    );
+                }
+            }
             Some(SystemProfileAction::CloseShell) | None => {}
         }
 

crates/console/prometeu-firmware/src/firmware/firmware_step_load_cartridge.rs

@@ -1,7 +1,8 @@
 use crate::firmware::firmware_state::{
-    AppCrashesStep, FirmwareState, GameRunningStep, ShellRunningStep,
+    AppCrashesStep, FirmwareState, GameRunningStep, HubHomeStep, ShellRunningStep,
 };
 use crate::firmware::prometeu_context::PrometeuContext;
+use crate::firmware::resident_game_termination;
 use prometeu_hal::app_mode::AppMode;
 use prometeu_hal::cartridge::Cartridge;
 use prometeu_hal::color::Color;
@@ -16,11 +17,28 @@ pub struct LoadCartridgeStep {
     init_error: Option<CrashReport>,
     loaded_task_id: Option<prometeu_system::task::TaskId>,
     loaded_app_mode: Option<AppMode>,
+    failure_recovery: LoadCartridgeFailureRecovery,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum LoadCartridgeFailureRecovery {
+    AppCrash,
+    ReturnToHub,
 }
 
 impl LoadCartridgeStep {
     pub fn new(cartridge: Cartridge) -> Self {
-        Self { cartridge, init_error: None, loaded_task_id: None, loaded_app_mode: None }
+        Self {
+            cartridge,
+            init_error: None,
+            loaded_task_id: None,
+            loaded_app_mode: None,
+            failure_recovery: LoadCartridgeFailureRecovery::AppCrash,
+        }
+    }
+
+    pub fn new_game_switch(cartridge: Cartridge) -> Self {
+        Self { failure_recovery: LoadCartridgeFailureRecovery::ReturnToHub, ..Self::new(cartridge) }
     }
 
     pub fn on_enter(&mut self, ctx: &mut PrometeuContext) {
@@ -31,6 +49,8 @@ impl LoadCartridgeStep {
             format!("Loading cartridge: {}", self.cartridge.title),
         );
 
+        ctx.platform.game2d_frame_composer().unbind_scene();
+
         // Initialize Asset Manager
         ctx.platform.assets_mut().initialize_for_cartridge(
             self.cartridge.asset_table.clone(),
@@ -51,6 +71,38 @@ impl LoadCartridgeStep {
 
     pub fn on_update(&mut self, ctx: &mut PrometeuContext) -> Option<FirmwareState> {
         if let Some(report) = self.init_error.take() {
+            if self.failure_recovery == LoadCartridgeFailureRecovery::ReturnToHub {
+                if self.cartridge.app_mode == AppMode::Game
+                    && let Some(task_id) = ctx.os.lifecycle().resident_game_task()
+                {
+                    let is_partial_target = ctx
+                        .os
+                        .sessions()
+                        .vm_session_for_task(task_id)
+                        .map(|session| session.app_id == self.cartridge.app_id)
+                        .unwrap_or(false);
+
+                    if is_partial_target {
+                        let _ = resident_game_termination::terminate_resident_game(
+                            ctx.os,
+                            ctx.platform,
+                            false,
+                        );
+                    }
+                }
+
+                ctx.os.log(
+                    LogLevel::Error,
+                    LogSource::Hub,
+                    0,
+                    format!(
+                        "Failed to switch to game {} app_id {}; returning to Home: {:?}",
+                        self.cartridge.title, self.cartridge.app_id, report
+                    ),
+                );
+                return Some(FirmwareState::HubHome(HubHomeStep));
+            }
+
             return Some(FirmwareState::AppCrashes(AppCrashesStep { report }));
         }
 

crates/console/prometeu-firmware/src/firmware/mod.rs

@@ -12,6 +12,7 @@ pub(crate) mod firmware_step_reset;
 pub(crate) mod firmware_step_shell_running;
 pub(crate) mod firmware_step_splash_screen;
 mod prometeu_context;
+pub(crate) mod resident_game_termination;
 
 pub use boot_target::BootTarget;
 pub use firmware::Firmware;

crates/console/prometeu-firmware/src/firmware/resident_game_termination.rs

@@ -0,0 +1,42 @@
+use prometeu_hal::RuntimePlatform;
+use prometeu_hal::app_mode::AppMode;
+use prometeu_hal::log::LogSource;
+use prometeu_system::task::TaskId;
+use prometeu_system::{LifecycleError, SystemOS};
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) enum ResidentGameTerminationOutcome {
+    NoResidentGame,
+    Terminated { task_id: TaskId, title: String },
+}
+
+pub(crate) fn terminate_resident_game(
+    os: &mut SystemOS,
+    platform: &mut dyn RuntimePlatform,
+    log_manual_hub_kill: bool,
+) -> Result<ResidentGameTerminationOutcome, LifecycleError> {
+    let Some(task_id) = os.lifecycle().resident_game_task() else {
+        return Ok(ResidentGameTerminationOutcome::NoResidentGame);
+    };
+
+    let title = os
+        .sessions()
+        .vm_session_for_task(task_id)
+        .map(|session| session.title.clone())
+        .unwrap_or_else(|| "<unknown>".to_string());
+
+    let terminated = os.lifecycle().terminate_resident_game()?;
+    let Some(task_id) = terminated else {
+        return Ok(ResidentGameTerminationOutcome::NoResidentGame);
+    };
+
+    os.vm().transition_render_owner(AppMode::Shell, 0);
+    platform.game2d_frame_composer().unbind_scene();
+    platform.assets_mut().shutdown();
+
+    if log_manual_hub_kill {
+        os.info(LogSource::Hub, format!("Resident game killed from Hub: {title}"));
+    }
+
+    Ok(ResidentGameTerminationOutcome::Terminated { task_id, title })
+}

crates/console/prometeu-system/src/lib.rs

@@ -8,7 +8,10 @@ pub use os::{
     DEFAULT_GAME_PAUSE_BUDGET_TICKS, GameLifecycleEvent, GameLifecycleEventKind, LifecycleError,
     LifecycleOperation, SessionError, SystemOS,
 };
-pub use programs::{NativeShellApp, PrometeuHub, SystemProfileAction, SystemProfileUpdate};
+pub use programs::{
+    HUB_SUSPENDED_GAME_KILL_CONTROL, NativeShellApp, PrometeuHub, SystemProfileAction,
+    SystemProfileUpdate,
+};
 pub use prometeu_hal::{RenderWorkerBackend, RenderWorkerFrameSink};
 pub use services::async_work::{
     AsyncWorkActiveJob, AsyncWorkCancelToken, AsyncWorkJobContext, AsyncWorkJobId,

crates/console/prometeu-system/src/os/facades/vm.rs

@@ -250,6 +250,12 @@ impl<'a> VmFacade<'a> {
     }
 
     pub fn active_render_ownership(&self) -> RenderOwnership {
+        if let Some(task_id) = self.foreground_session_task_id()
+            && let Some(session) = self.os.vm_sessions.for_task(task_id)
+        {
+            return session.runtime.render_manager.active_ownership();
+        }
+
         self.os.vm_runtime.render_manager.active_ownership()
     }
 
@@ -317,4 +323,8 @@ impl<'a> VmFacade<'a> {
             .foreground_task()
             .or_else(|| self.os.foreground_stack.resident_game_task())
     }
+
+    fn foreground_session_task_id(&self) -> Option<TaskId> {
+        self.os.task_manager.foreground_task()
+    }
 }

crates/console/prometeu-system/src/programs/mod.rs

@@ -1,3 +1,6 @@
 mod prometeu_hub;
 
-pub use prometeu_hub::{NativeShellApp, PrometeuHub, SystemProfileAction, SystemProfileUpdate};
+pub use prometeu_hub::{
+    HUB_SUSPENDED_GAME_KILL_CONTROL, NativeShellApp, PrometeuHub, SystemProfileAction,
+    SystemProfileUpdate,
+};

crates/console/prometeu-system/src/programs/prometeu_hub/mod.rs

@@ -1,4 +1,7 @@
 #[allow(clippy::module_inception)]
 mod prometeu_hub;
 
-pub use prometeu_hub::{NativeShellApp, PrometeuHub, SystemProfileAction, SystemProfileUpdate};
+pub use prometeu_hub::{
+    HUB_SUSPENDED_GAME_KILL_CONTROL, NativeShellApp, PrometeuHub, SystemProfileAction,
+    SystemProfileUpdate,
+};

crates/console/prometeu-system/src/programs/prometeu_hub/prometeu_hub.rs

@@ -1,5 +1,6 @@
 use crate::task::TaskId;
 use crate::{CrashReport, GameLibrary, GameSwitchTarget, SystemOS};
+use prometeu_hal::app_mode::AppMode;
 use prometeu_hal::color::Color;
 use prometeu_hal::primitives::Rect;
 use prometeu_hal::{
@@ -19,6 +20,7 @@ const GAME_ROW_W: i32 = 336;
 const GAME_ROW_H: i32 = 22;
 const GAME_ROW_GAP: i32 = 6;
 const MAX_HOME_GAME_ROWS: usize = 3;
+pub const HUB_SUSPENDED_GAME_KILL_CONTROL: Rect = Rect { x: 288, y: 230, w: 168, h: 24 };
 #[cfg(test)]
 const SHELL_FRAME: Rect = Rect { x: 40, y: 20, w: 400, h: 220 };
 
@@ -31,6 +33,8 @@ const COLOR_TEXT: Color = Color::rgb(230, 236, 224);
 const COLOR_MUTED: Color = Color::rgb(91, 112, 128);
 const COLOR_BUTTON: Color = Color::rgb(45, 59, 82);
 const COLOR_BUTTON_ACTIVE: Color = Color::rgb(72, 91, 122);
+const COLOR_KILL: Color = Color::rgb(164, 32, 40);
+const COLOR_KILL_ACTIVE: Color = Color::rgb(206, 46, 54);
 
 /// PrometeuHub: Launcher and system UI environment.
 pub struct PrometeuHub {
@@ -83,6 +87,7 @@ impl NativeShellApp {
 pub enum SystemProfileAction {
     LaunchNativeShell(NativeShellApp),
     LaunchGame { target: GameSwitchTarget },
+    KillResidentGame,
     CloseShell,
 }
 
@@ -131,12 +136,14 @@ impl PrometeuHub {
         }
 
         let input = platform.input();
+        let suspended_game = if in_shell { None } else { resident_game_indicator(os) };
         if let Some(action) = action_for_click(
             in_shell,
             input.touch().x(),
             input.touch().y(),
             input.touch().f().pressed,
             self.game_library.entries(),
+            suspended_game.as_ref(),
         ) {
             return Some(action);
         }
@@ -149,7 +156,13 @@ impl PrometeuHub {
         let pointer_y = platform.input().touch().y();
 
         let packet = if os.windows().window_count() == 0 {
-            render_home_packet(pointer_x, pointer_y, self.game_library.entries())
+            let suspended_game = resident_game_indicator(os);
+            render_home_packet(
+                pointer_x,
+                pointer_y,
+                self.game_library.entries(),
+                suspended_game.as_ref(),
+            )
         } else {
             let mut commands = Vec::new();
             for window in os.windows().windows() {
@@ -232,6 +245,7 @@ fn action_for_click(
     y: i32,
     pressed: bool,
     game_entries: &[crate::GameLibraryEntry],
+    suspended_game: Option<&SuspendedGameIndicator>,
 ) -> Option<SystemProfileAction> {
     if !pressed {
         return None;
@@ -241,6 +255,10 @@ fn action_for_click(
         return rect_contains(CLOSE_BUTTON, x, y).then_some(SystemProfileAction::CloseShell);
     }
 
+    if suspended_game.is_some() && rect_contains(HUB_SUSPENDED_GAME_KILL_CONTROL, x, y) {
+        return Some(SystemProfileAction::KillResidentGame);
+    }
+
     if let Some(entry) = game_entries
         .iter()
         .take(MAX_HOME_GAME_ROWS)
@@ -257,6 +275,23 @@ fn action_for_click(
         .map(|button| SystemProfileAction::LaunchNativeShell(button.app))
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct SuspendedGameIndicator {
+    title: String,
+}
+
+fn resident_game_indicator(os: &mut SystemOS) -> Option<SuspendedGameIndicator> {
+    let task_id = os.lifecycle().resident_game_task()?;
+    let sessions = os.sessions();
+    let session = sessions.vm_session_for_task(task_id)?;
+
+    if session.app_mode != AppMode::Game {
+        return None;
+    }
+
+    Some(SuspendedGameIndicator { title: session.title.clone() })
+}
+
 fn game_row_rect(index: usize) -> Rect {
     Rect {
         x: GAME_ROW_X,
@@ -281,6 +316,7 @@ fn render_home_packet(
     pointer_x: i32,
     pointer_y: i32,
     game_entries: &[crate::GameLibraryEntry],
+    suspended_game: Option<&SuspendedGameIndicator>,
 ) -> ShellUiFramePacket {
     let mut commands = Vec::new();
     commands.push(GfxUiCommand::Clear { color: COLOR_BG });
@@ -320,6 +356,11 @@ fn render_home_packet(
         draw_button(&mut commands, button.rect, button.label, hovered);
     }
 
+    if let Some(suspended_game) = suspended_game {
+        let hovered = rect_contains(HUB_SUSPENDED_GAME_KILL_CONTROL, pointer_x, pointer_y);
+        draw_suspended_game_kill_control(&mut commands, suspended_game, hovered);
+    }
+
     ShellUiFramePacket::new(commands)
 }
 
@@ -422,6 +463,39 @@ fn draw_game_row(commands: &mut Vec<GfxUiCommand>, rect: Rect, label: &str, hove
     draw_buffer_text(commands, rect.x + 8, rect.y + 7, label, COLOR_TEXT);
 }
 
+fn draw_suspended_game_kill_control(
+    commands: &mut Vec<GfxUiCommand>,
+    suspended_game: &SuspendedGameIndicator,
+    hovered: bool,
+) {
+    let fill = if hovered { COLOR_KILL_ACTIVE } else { COLOR_KILL };
+    let border = if hovered { COLOR_HILITE } else { COLOR_BORDER };
+    fill_rect(commands, HUB_SUSPENDED_GAME_KILL_CONTROL, fill);
+    draw_rect(commands, HUB_SUSPENDED_GAME_KILL_CONTROL, border);
+    draw_buffer_text(
+        commands,
+        HUB_SUSPENDED_GAME_KILL_CONTROL.x + 8,
+        HUB_SUSPENDED_GAME_KILL_CONTROL.y + 8,
+        &fit_text_to_control(&suspended_game.title, HUB_SUSPENDED_GAME_KILL_CONTROL.w - 16),
+        COLOR_TEXT,
+    );
+}
+
+fn fit_text_to_control(text: &str, max_width: i32) -> String {
+    let max_chars = (max_width / 8).max(0) as usize;
+    if text.chars().count() <= max_chars {
+        return text.to_string();
+    }
+
+    if max_chars <= 2 {
+        return text.chars().take(max_chars).collect();
+    }
+
+    let mut fitted: String = text.chars().take(max_chars - 2).collect();
+    fitted.push_str("..");
+    fitted
+}
+
 fn draw_buffer_text(commands: &mut Vec<GfxUiCommand>, x: i32, y: i32, text: &str, color: Color) {
     commands.push(GfxUiCommand::DrawText { x, y, text: text.to_string(), color });
 }
@@ -462,7 +536,14 @@ mod tests {
     #[test]
     fn shell_a_button_click_emits_launch_action() {
         assert_eq!(
-            action_for_click(false, HOME_BUTTONS[0].rect.x, HOME_BUTTONS[0].rect.y, true, &[]),
+            action_for_click(
+                false,
+                HOME_BUTTONS[0].rect.x,
+                HOME_BUTTONS[0].rect.y,
+                true,
+                &[],
+                None
+            ),
             Some(SystemProfileAction::LaunchNativeShell(NativeShellApp::ShellA))
         );
     }
@@ -475,7 +556,8 @@ mod tests {
                 SHELL_B_BUTTON.x + SHELL_B_BUTTON.w - 1,
                 SHELL_B_BUTTON.y,
                 true,
-                &[]
+                &[],
+                None
             ),
             Some(SystemProfileAction::LaunchNativeShell(NativeShellApp::ShellB))
         );
@@ -489,7 +571,8 @@ mod tests {
                 SHELL_A_BUTTON.x + SHELL_A_BUTTON.w,
                 SHELL_A_BUTTON.y,
                 true,
-                &[]
+                &[],
+                None
             ),
             None
         );
@@ -499,7 +582,8 @@ mod tests {
                 SHELL_A_BUTTON.x,
                 SHELL_A_BUTTON.y + SHELL_A_BUTTON.h,
                 true,
-                &[]
+                &[],
+                None
             ),
             None
         );
@@ -507,7 +591,10 @@ mod tests {
 
     #[test]
     fn held_pointer_does_not_emit_click_action() {
-        assert_eq!(action_for_click(false, SHELL_A_BUTTON.x, SHELL_A_BUTTON.y, false, &[]), None);
+        assert_eq!(
+            action_for_click(false, SHELL_A_BUTTON.x, SHELL_A_BUTTON.y, false, &[], None),
+            None
+        );
     }
 
     #[test]
@@ -535,8 +622,14 @@ mod tests {
             discovered_at: std::time::SystemTime::UNIX_EPOCH,
         };
 
-        let action =
+        let action = action_for_click(
-            action_for_click(false, GAME_ROW_X, GAME_ROW_Y, true, std::slice::from_ref(&entry));
+            false,
+            GAME_ROW_X,
+            GAME_ROW_Y,
+            true,
+            std::slice::from_ref(&entry),
+            None,
+        );
 
         assert_eq!(
             action,
@@ -554,10 +647,10 @@ mod tests {
     #[test]
     fn close_button_click_emits_close_only_in_shell() {
         assert_eq!(
-            action_for_click(true, CLOSE_BUTTON.x, CLOSE_BUTTON.y, true, &[]),
+            action_for_click(true, CLOSE_BUTTON.x, CLOSE_BUTTON.y, true, &[], None),
             Some(SystemProfileAction::CloseShell)
         );
-        assert_eq!(action_for_click(false, CLOSE_BUTTON.x, CLOSE_BUTTON.y, true, &[]), None);
+        assert_eq!(action_for_click(false, CLOSE_BUTTON.x, CLOSE_BUTTON.y, true, &[], None), None);
     }
 
     #[test]
@@ -571,7 +664,7 @@ mod tests {
 
     #[test]
     fn home_render_produces_shell_ui_packet_commands() {
-        let packet = render_home_packet(SHELL_A_BUTTON.x, SHELL_A_BUTTON.y, &[]);
+        let packet = render_home_packet(SHELL_A_BUTTON.x, SHELL_A_BUTTON.y, &[], None);
 
         assert!(matches!(packet.commands.first(), Some(GfxUiCommand::Clear { .. })));
         assert!(packet.commands.iter().any(|command| {
@@ -579,6 +672,123 @@ mod tests {
         }));
     }
 
+    #[test]
+    fn resident_game_indicator_uses_only_resident_game_sessions() {
+        let mut os = SystemOS::new(None);
+        assert_eq!(resident_game_indicator(&mut os), None);
+
+        let shell = os.sessions().create_vm_shell_task(7, "VM Shell");
+        assert_eq!(resident_game_indicator(&mut os), None);
+        os.lifecycle().suspend_task(shell).expect("shell suspend should succeed");
+        assert_eq!(resident_game_indicator(&mut os), None);
+
+        let game = os.sessions().create_vm_game_task(42, "Stress Console");
+        os.lifecycle().suspend_task(game).expect("game suspend should succeed");
+
+        assert_eq!(
+            resident_game_indicator(&mut os),
+            Some(SuspendedGameIndicator { title: "Stress Console".to_string() })
+        );
+    }
+
+    #[test]
+    fn home_render_shows_suspended_game_kill_control_when_game_is_resident() {
+        let suspended_game = SuspendedGameIndicator { title: "Stress Console".to_string() };
+        let packet = render_home_packet(
+            HUB_SUSPENDED_GAME_KILL_CONTROL.x,
+            HUB_SUSPENDED_GAME_KILL_CONTROL.y,
+            &[],
+            Some(&suspended_game),
+        );
+
+        assert!(packet.commands.iter().any(|command| {
+            matches!(
+                command,
+                GfxUiCommand::FillRect { rect, color }
+                    if *rect == HUB_SUSPENDED_GAME_KILL_CONTROL && *color == COLOR_KILL_ACTIVE
+            )
+        }));
+        assert!(packet.commands.iter().any(|command| {
+            matches!(
+                command,
+                GfxUiCommand::DrawText { x, y, text, .. }
+                    if *x == HUB_SUSPENDED_GAME_KILL_CONTROL.x + 8
+                        && *y == HUB_SUSPENDED_GAME_KILL_CONTROL.y + 8
+                        && text == "Stress Console"
+            )
+        }));
+    }
+
+    #[test]
+    fn home_render_omits_suspended_game_kill_control_without_resident_game() {
+        let packet = render_home_packet(
+            HUB_SUSPENDED_GAME_KILL_CONTROL.x,
+            HUB_SUSPENDED_GAME_KILL_CONTROL.y,
+            &[],
+            None,
+        );
+
+        assert!(!packet.commands.iter().any(|command| {
+            matches!(
+                command,
+                GfxUiCommand::FillRect { rect, color }
+                    if *rect == HUB_SUSPENDED_GAME_KILL_CONTROL
+                        && (*color == COLOR_KILL || *color == COLOR_KILL_ACTIVE)
+            )
+        }));
+    }
+
+    #[test]
+    fn suspended_game_kill_control_click_emits_kill_action() {
+        let suspended_game = SuspendedGameIndicator { title: "Stress Console".to_string() };
+
+        assert_eq!(
+            action_for_click(
+                false,
+                HUB_SUSPENDED_GAME_KILL_CONTROL.x,
+                HUB_SUSPENDED_GAME_KILL_CONTROL.y,
+                true,
+                &[],
+                Some(&suspended_game),
+            ),
+            Some(SystemProfileAction::KillResidentGame)
+        );
+        assert_eq!(
+            action_for_click(
+                false,
+                HUB_SUSPENDED_GAME_KILL_CONTROL.x,
+                HUB_SUSPENDED_GAME_KILL_CONTROL.y,
+                true,
+                &[],
+                None,
+            ),
+            None
+        );
+    }
+
+    #[test]
+    fn suspended_game_kill_control_truncates_long_titles() {
+        let long_title =
+            SuspendedGameIndicator { title: "Extremely Long Resident Game Title".to_string() };
+        let packet = render_home_packet(0, 0, &[], Some(&long_title));
+        let label = packet
+            .commands
+            .iter()
+            .find_map(|command| match command {
+                GfxUiCommand::DrawText { x, y, text, .. }
+                    if *x == HUB_SUSPENDED_GAME_KILL_CONTROL.x + 8
+                        && *y == HUB_SUSPENDED_GAME_KILL_CONTROL.y + 8 =>
+                {
+                    Some(text)
+                }
+                _ => None,
+            })
+            .expect("kill control text should render");
+
+        assert!(label.ends_with(".."));
+        assert!(label.chars().count() <= ((HUB_SUSPENDED_GAME_KILL_CONTROL.w - 16) / 8) as usize);
+    }
+
     #[test]
     fn shell_close_button_sits_inside_shell_frame() {
         assert!(rect_contains(SHELL_FRAME, CLOSE_BUTTON.x, CLOSE_BUTTON.y));

crates/console/prometeu-system/src/services/game_library.rs

@@ -315,4 +315,22 @@ mod tests {
         assert_eq!(library.diagnostics().len(), 1);
         assert_eq!(library.diagnostics()[0].reason, GameLibraryDiagnosticReason::RootNotDirectory);
     }
+
+    #[test]
+    fn repository_test_cartridges_include_stress_and_dummy_boy() {
+        let games_root =
+            PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../../..").join("test-cartridges");
+
+        let library = discover_games_root(games_root);
+        let entries = library.entries();
+
+        assert!(entries.iter().any(|entry| {
+            entry.app_id == 1
+                && entry.title == "Stress Console"
+                && entry.path.ends_with("stress-console")
+        }));
+        assert!(entries.iter().any(|entry| {
+            entry.app_id == 2 && entry.title == "Dummy Boy" && entry.path.ends_with("dummy-boy")
+        }));
+    }
 }

crates/host/prometeu-host-desktop-winit/src/runner.rs

@@ -26,16 +26,22 @@ const IDLE_HOST_POLL_DT: Duration = Duration::from_millis(100);
 
 #[derive(Debug, Clone)]
 struct PresentationState {
-    latest_published_frame: u64,
+    latest_published_frame: Option<PresentationFrameMarker>,
-    last_presented_frame: Option<u64>,
+    last_presented_frame: Option<PresentationFrameMarker>,
     host_invalidated: bool,
     redraw_requested: bool,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct PresentationFrameMarker {
+    ownership: RenderOwnership,
+    frame_id: u64,
+}
+
 impl Default for PresentationState {
     fn default() -> Self {
         Self {
-            latest_published_frame: 0,
+            latest_published_frame: None,
             last_presented_frame: None,
             host_invalidated: true,
             redraw_requested: false,
@@ -44,9 +50,10 @@ impl Default for PresentationState {
 }
 
 impl PresentationState {
-    fn note_published_frame(&mut self, frame_index: u64) {
+    fn note_published_frame(&mut self, ownership: RenderOwnership, frame_id: u64) {
-        if frame_index > self.latest_published_frame {
+        let marker = PresentationFrameMarker { ownership, frame_id };
-            self.latest_published_frame = frame_index;
+        if self.latest_published_frame != Some(marker) {
+            self.latest_published_frame = Some(marker);
         }
     }
 
@@ -55,7 +62,7 @@ impl PresentationState {
     }
 
     fn needs_redraw(&self) -> bool {
-        self.host_invalidated || self.last_presented_frame != Some(self.latest_published_frame)
+        self.host_invalidated || self.last_presented_frame != self.latest_published_frame
     }
 
     fn should_request_redraw(&mut self) -> bool {
@@ -70,7 +77,7 @@ impl PresentationState {
     fn mark_presented(&mut self) {
         self.redraw_requested = false;
         self.host_invalidated = false;
-        self.last_presented_frame = Some(self.latest_published_frame);
+        self.last_presented_frame = self.latest_published_frame;
     }
 }
 
@@ -437,9 +444,11 @@ impl ApplicationHandler for HostRunner {
         if let Some(worker_frame) = self.render_frame_store.latest_frame()
             && should_present_worker_frame(&self.firmware.state, &worker_frame, active_ownership)
         {
-            self.presentation.note_published_frame(worker_frame.frame_id.get());
+            self.presentation
+                .note_published_frame(worker_frame.ownership, worker_frame.frame_id.get());
         } else {
-            self.presentation.note_published_frame(self.firmware.os.frame_index());
+            self.presentation
+                .note_published_frame(active_ownership, self.firmware.os.frame_index());
         }
 
         if was_debugger_connected != self.debugger.stream.is_some()
@@ -505,14 +514,37 @@ mod tests {
 
     #[test]
     fn presentation_state_requests_redraw_for_new_frame_publication() {
+        let ownership = RenderOwnership::new(1, AppMode::Game, 1);
         let mut state = PresentationState::default();
         state.mark_presented();
 
-        state.note_published_frame(1);
+        state.note_published_frame(ownership, 1);
 
         assert!(state.should_request_redraw());
         state.mark_presented();
-        assert_eq!(state.last_presented_frame, Some(1));
+        assert_eq!(
+            state.last_presented_frame,
+            Some(PresentationFrameMarker { ownership, frame_id: 1 })
+        );
+    }
+
+    #[test]
+    fn presentation_state_requests_redraw_when_ownership_changes_with_lower_frame_id() {
+        let first = RenderOwnership::new(3, AppMode::Game, 1);
+        let next = RenderOwnership::new(4, AppMode::Game, 2);
+        let mut state = PresentationState::default();
+
+        state.note_published_frame(first, 120);
+        state.mark_presented();
+
+        state.note_published_frame(next, 0);
+
+        assert!(state.should_request_redraw());
+        state.mark_presented();
+        assert_eq!(
+            state.last_presented_frame,
+            Some(PresentationFrameMarker { ownership: next, frame_id: 0 })
+        );
     }
 
     #[test]
@@ -608,11 +640,14 @@ mod tests {
         let mut presentation = PresentationState::default();
         presentation.mark_presented();
         let published = store.latest_frame().expect("published frame");
-        presentation.note_published_frame(published.frame_id.get());
+        presentation.note_published_frame(published.ownership, published.frame_id.get());
 
         assert!(presentation.should_request_redraw());
         presentation.mark_presented();
-        assert_eq!(presentation.last_presented_frame, Some(9));
+        assert_eq!(
+            presentation.last_presented_frame,
+            Some(PresentationFrameMarker { ownership: published.ownership, frame_id: 9 })
+        );
     }
 
     #[test]

crates/tools/pbxgen-dummy-boy/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "pbxgen-dummy-boy"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "1"
+prometeu-bytecode = { path = "../../console/prometeu-bytecode" }
+prometeu-hal = { path = "../../console/prometeu-hal" }
+
+[dev-dependencies]
+serde_json = "1"

crates/tools/pbxgen-dummy-boy/src/lib.rs

@@ -0,0 +1,147 @@
+use anyhow::Result;
+use prometeu_bytecode::assembler::assemble;
+use prometeu_bytecode::model::{BytecodeModule, DebugInfo, Export, FunctionMeta, SyscallDecl};
+use prometeu_hal::color::Color;
+use std::fs;
+use std::path::PathBuf;
+
+const APP_ID: u32 = 2;
+const TITLE: &str = "Dummy Boy";
+const APP_VERSION: &str = "0.1.0";
+
+fn asm(s: &str) -> Vec<u8> {
+    assemble(s).expect("assemble")
+}
+
+pub fn generate() -> Result<()> {
+    let out_dir = cartridge_dir();
+    fs::create_dir_all(&out_dir)?;
+    fs::write(out_dir.join("program.pbx"), build_program())?;
+    fs::write(out_dir.join("manifest.json"), manifest_json())?;
+    Ok(())
+}
+
+pub fn build_program() -> Vec<u8> {
+    let mut rom = Vec::new();
+
+    rom.extend(asm("GET_GLOBAL 0\nPUSH_I32 1\nADD\nSET_GLOBAL 0"));
+    rom.extend(asm(&format!("PUSH_I64 {}\nHOSTCALL 0", Color::BLACK.raw())));
+
+    rom.extend(asm("GET_GLOBAL 0\nPUSH_I32 3\nMOD\nPUSH_I32 0\nEQ"));
+    let jump_to_green_case_offset = rom.len() + 2;
+    rom.extend(asm("JMP_IF_FALSE 0"));
+    rom.extend(asm(&format!("PUSH_I64 {}\nSET_LOCAL 0", Color::RED.raw())));
+    let jump_to_draw_after_red_offset = rom.len() + 2;
+    rom.extend(asm("JMP 0"));
+
+    let green_case = rom.len() as u32;
+    rom.extend(asm("GET_GLOBAL 0\nPUSH_I32 3\nMOD\nPUSH_I32 1\nEQ"));
+    let jump_to_blue_case_offset = rom.len() + 2;
+    rom.extend(asm("JMP_IF_FALSE 0"));
+    rom.extend(asm(&format!("PUSH_I64 {}\nSET_LOCAL 0", Color::GREEN.raw())));
+    let jump_to_draw_after_green_offset = rom.len() + 2;
+    rom.extend(asm("JMP 0"));
+
+    let blue_case = rom.len() as u32;
+    rom.extend(asm(&format!("PUSH_I64 {}\nSET_LOCAL 0", Color::BLUE.raw())));
+
+    let draw = rom.len() as u32;
+    rom.extend(asm(&format!(
+        "PUSH_I32 180\n\
+         PUSH_I32 75\n\
+         PUSH_I32 120\n\
+         PUSH_I32 120\n\
+         PUSH_I64 {}\n\
+         GET_LOCAL 0\n\
+         HOSTCALL 1\n\
+         FRAME_SYNC\n\
+         RET",
+        Color::WHITE.raw()
+    )));
+
+    patch_jump(&mut rom, jump_to_green_case_offset, green_case);
+    patch_jump(&mut rom, jump_to_draw_after_red_offset, draw);
+    patch_jump(&mut rom, jump_to_blue_case_offset, blue_case);
+    patch_jump(&mut rom, jump_to_draw_after_green_offset, draw);
+
+    BytecodeModule {
+        version: 0,
+        const_pool: vec![],
+        functions: vec![FunctionMeta {
+            code_offset: 0,
+            code_len: rom.len() as u32,
+            param_slots: 0,
+            local_slots: 1,
+            return_slots: 0,
+            max_stack_slots: 8,
+        }],
+        code: rom,
+        debug_info: Some(DebugInfo {
+            pc_to_span: vec![],
+            function_names: vec![(0, "main".into())],
+        }),
+        exports: vec![Export { symbol: "main".into(), func_idx: 0 }],
+        syscalls: vec![
+            SyscallDecl {
+                module: "gfx2d".into(),
+                name: "clear".into(),
+                version: 1,
+                arg_slots: 1,
+                ret_slots: 0,
+            },
+            SyscallDecl {
+                module: "gfx2d".into(),
+                name: "draw_square".into(),
+                version: 1,
+                arg_slots: 6,
+                ret_slots: 0,
+            },
+        ],
+    }
+    .serialize()
+}
+
+pub fn manifest_json() -> Vec<u8> {
+    format!(
+        "{{\n  \"magic\": \"PMTU\",\n  \"cartridge_version\": 1,\n  \"app_id\": {APP_ID},\n  \"title\": \"{TITLE}\",\n  \"app_version\": \"{APP_VERSION}\",\n  \"app_mode\": \"Game\",\n  \"capabilities\": [\"gfx2d\"]\n}}\n"
+    )
+    .into_bytes()
+}
+
+fn cartridge_dir() -> PathBuf {
+    let mut out_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    out_dir.pop();
+    out_dir.pop();
+    out_dir.pop();
+    out_dir.push("test-cartridges");
+    out_dir.push("dummy-boy");
+    out_dir
+}
+
+fn patch_jump(buf: &mut [u8], imm_offset: usize, target: u32) {
+    buf[imm_offset..imm_offset + 4].copy_from_slice(&target.to_le_bytes());
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generated_program_is_pbx_module_with_expected_syscalls() {
+        let bytes = build_program();
+
+        assert!(bytes.starts_with(b"PBS\0"));
+        assert!(bytes.len() > 64);
+    }
+
+    #[test]
+    fn manifest_declares_distinct_game_identity() {
+        let manifest: serde_json::Value =
+            serde_json::from_slice(&manifest_json()).expect("manifest should parse");
+
+        assert_eq!(manifest["app_id"], APP_ID);
+        assert_eq!(manifest["title"], TITLE);
+        assert_eq!(manifest["app_mode"], "Game");
+        assert_eq!(manifest["capabilities"], serde_json::json!(["gfx2d"]));
+    }
+}

crates/tools/pbxgen-dummy-boy/src/main.rs

@@ -0,0 +1,5 @@
+use anyhow::Result;
+
+fn main() -> Result<()> {
+    pbxgen_dummy_boy::generate()
+}

discussion/index.ndjson

@@ -1,5 +1,6 @@
-{"type":"meta","next_id":{"DSC":44,"AGD":47,"DEC":40,"PLN":163,"LSN":53,"CLSN":1}}
+{"type":"meta","next_id":{"DSC":45,"AGD":48,"DEC":41,"PLN":167,"LSN":55,"CLSN":1}}
-{"type":"discussion","id":"DSC-0043","status":"in_progress","ticket":"system-os-cartridge-switch-orchestrator","title":"SystemOS Cartridge Switch Orchestrator","created_at":"2026-07-03","updated_at":"2026-07-05","tags":["runtime","os","lifecycle","game","cartridge","architecture"],"agendas":[{"id":"AGD-0044","file":"AGD-0044-systemos-cartridge-switch-orchestrator.md","status":"accepted","created_at":"2026-07-03","updated_at":"2026-07-05"}],"decisions":[{"id":"DEC-0039","file":"DEC-0039-systemos-game-cartridge-switch-orchestrator.md","status":"accepted","created_at":"2026-07-05","updated_at":"2026-07-05","ref_agenda":"AGD-0044"}],"plans":[{"id":"PLN-0157","file":"PLN-0157-introduce-systemos-game-switch-target-contract.md","status":"done","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]},{"id":"PLN-0158","file":"PLN-0158-terminate-resident-game-before-switching-cartridges.md","status":"done","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]},{"id":"PLN-0159","file":"PLN-0159-recover-failed-game-switches-back-to-home.md","status":"open","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]},{"id":"PLN-0160","file":"PLN-0160-add-dummy-boy-visual-switch-test-cartridge.md","status":"open","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]},{"id":"PLN-0161","file":"PLN-0161-validate-stress-to-dummy-boy-game-switch-end-to-end.md","status":"open","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]},{"id":"PLN-0162","file":"PLN-0162-specify-game-switch-contract-and-direct-boot-separation.md","status":"open","created_at":"2026-07-05","updated_at":"2026-07-05","ref_decisions":["DEC-0039"]}],"lessons":[]}
+{"type":"discussion","id":"DSC-0044","status":"done","ticket":"hub-suspended-game-kill-affordance","title":"Hub Suspended Game Kill Affordance","created_at":"2026-07-05","updated_at":"2026-07-05","tags":["hub","lifecycle","game","ui"],"agendas":[],"decisions":[],"plans":[],"lessons":[{"id":"LSN-0054","file":"discussion/lessons/DSC-0044-hub-suspended-game-kill-affordance/LSN-0054-manual-hub-kill-must-share-game-termination-cleanup.md","status":"done","created_at":"2026-07-05","updated_at":"2026-07-05"}]}
+{"type":"discussion","id":"DSC-0043","status":"done","ticket":"system-os-cartridge-switch-orchestrator","title":"SystemOS Cartridge Switch Orchestrator","created_at":"2026-07-03","updated_at":"2026-07-05","tags":["runtime","os","lifecycle","game","cartridge","architecture"],"agendas":[],"decisions":[],"plans":[],"lessons":[{"id":"LSN-0053","file":"discussion/lessons/DSC-0043-system-os-cartridge-switch-orchestrator/LSN-0053-game-switching-is-lifecycle-replacement-not-loader-work.md","status":"done","created_at":"2026-07-05","updated_at":"2026-07-05"}]}
 {"type":"discussion","id":"DSC-0039","status":"abandoned","ticket":"render-pipeline-family-and-future-3d","title":"Render Pipeline Family and Future 3D","created_at":"2026-06-04","updated_at":"2026-06-04","tags":["gfx","renderer","runtime","architecture","pipeline"],"agendas":[{"id":"AGD-0039","file":"AGD-0039-render-pipeline-family-and-future-3d.md","status":"abandoned","created_at":"2026-06-04","updated_at":"2026-06-04","_override_reason":"User explicitly chose to close this agenda without a new decision because DSC-0038 already established enough architecture for future extension, and 3D is intentionally deferred."}],"decisions":[],"plans":[],"lessons":[],"_override_reason":"User explicitly chose to close this agenda without a new decision because DSC-0038 already established enough architecture for future extension, and 3D is intentionally deferred."}
 {"type":"discussion","id":"DSC-0040","status":"done","ticket":"vm-render-parallel-execution-boundary","title":"VM and Render Parallel Execution Boundary","created_at":"2026-06-04","updated_at":"2026-06-06","tags":["runtime","renderer","vm","concurrency","architecture","perf"],"agendas":[],"decisions":[],"plans":[],"lessons":[{"id":"LSN-0048","file":"discussion/lessons/DSC-0040-vm-render-parallel-execution-boundary/LSN-0048-render-workers-need-a-closed-packet-contract.md","status":"done","created_at":"2026-06-06","updated_at":"2026-06-06"}]}
 {"type":"discussion","id":"DSC-0041","status":"done","ticket":"foreground-stack-game-pause-shell-vm-backed","title":"Foreground Stack, Game Pause, and VM-Backed Shell Coexistence","created_at":"2026-06-05","updated_at":"2026-07-05","tags":["runtime","os","lifecycle","shell","game","vm","foreground","architecture"],"agendas":[],"decisions":[],"plans":[],"lessons":[{"id":"LSN-0052","file":"discussion/lessons/DSC-0041-foreground-stack-game-pause-shell-vm-backed/LSN-0052-foreground-ownership-and-vm-session-ownership-are-separate.md","status":"done","created_at":"2026-07-05","updated_at":"2026-07-05"}]}

discussion/lessons/DSC-0043-system-os-cartridge-switch-orchestrator/LSN-0053-game-switching-is-lifecycle-replacement-not-loader-work.md

@@ -0,0 +1,67 @@
+---
+id: LSN-0053
+ticket: system-os-cartridge-switch-orchestrator
+title: Game Switching Is Lifecycle Replacement, Not Loader Work
+created: 2026-07-05
+tags: [runtime, os, lifecycle, game, cartridge]
+---
+
+## Context
+
+PROMETEU supports two superficially similar flows:
+
+- `Game -> Home -> same Game`, which is pause/suspend/resume.
+- `Game A -> Home -> Game B`, which is destructive replacement.
+
+The second flow is not a loader feature. It is a SystemOS lifecycle operation
+that happens to use the cartridge loader after the old resident Game has been
+removed from resumable state.
+
+## Key Decisions
+
+### SystemOS Game Cartridge Switch Orchestrator
+
+**What:** A different-Game launch from Home terminates the previous resident
+Game before loading the new cartridge. The new Game receives a fresh VM session.
+
+**Why:** Reusing or preserving the old Game while the new Game loads creates a
+rollback problem across VM state, handles, assets, input, audio, render
+ownership, debug state, and lifecycle delivery. V1 does not need that
+transactional model.
+
+**Trade-offs:** Failed replacement returns to Home and does not restore the old
+Game. This is intentionally simpler than snapshot/rollback and makes state
+ownership visible in tests.
+
+## Patterns and Algorithms
+
+Use a resolved SystemOS switch target, not a guest syscall, for Home launches.
+The target carries cartridge path and identity, while SystemOS owns the policy:
+
+1. detect whether the selected Game matches the resident `app_id`;
+2. resume if it is the same Game;
+3. terminate the old resident Game if it is different;
+4. load the new cartridge through the normal loader;
+5. create and initialize a fresh VM session;
+6. return to Home on replacement failure without restoring the previous Game.
+
+The loader stays a materializer. It does not close tasks, remove sessions,
+repair foreground state, or own failure recovery.
+
+## Pitfalls
+
+- Treating a different Game as a resume path leaks VM execution state.
+- Letting the loader own lifecycle cleanup hides policy in the wrong layer.
+- Keeping the old Game as rollback state requires correctness across assets,
+  render ownership, input barriers, audio, open handles, and debugger state.
+- A switch test with only one cartridge cannot prove identity replacement.
+
+## Takeaways
+
+- Same-Game Home selection is resume; different-Game Home selection is
+  destructive replacement.
+- SystemOS owns cartridge switching policy; the cartridge loader only loads.
+- Replacement failure should be a clean Home state, not a rollback to the old
+  Game.
+- End-to-end switch tests need visually distinct cartridges to catch stale
+  session or stale frame reuse.

discussion/lessons/DSC-0044-hub-suspended-game-kill-affordance/LSN-0054-manual-hub-kill-must-share-game-termination-cleanup.md

@@ -0,0 +1,72 @@
+---
+id: LSN-0054
+ticket: hub-suspended-game-kill-affordance
+title: Manual Hub Kill Must Share Game Termination Cleanup
+created: 2026-07-05
+tags: [hub, lifecycle, game, ui, assets]
+---
+
+## Context
+
+After a Game returns to Home, the Game can remain resident and suspended so it
+can be resumed later. That state needs a visible, direct way to terminate the
+resident Game without launching another cartridge just to force replacement.
+
+The Hub kill affordance solved the UX gap, but the durable engineering lesson is
+the cleanup boundary: manual kill must not become a second, partial termination
+path.
+
+## Key Decisions
+
+### Hub Suspended Game Kill Affordance
+
+**What:** Hub renders a red bottom-right control when a Game is resident and
+suspended. The control shows only the Game title. Clicking it immediately
+terminates the resident Game and keeps the user in Hub.
+
+**Why:** The user can distinguish "resume this Game" from "discard this resident
+Game" without starting a different cartridge. Reusing the canonical termination
+path prevents a repeat of stale scene/glyph/asset state bugs.
+
+**Trade-offs:** V1 has no confirmation step. The destructive nature is carried
+by placement, color, and the fact that the target Game is already out of
+foreground.
+
+## Patterns and Algorithms
+
+Manual Hub kill and destructive Game replacement should call the same resident
+Game termination helper. That helper is responsible for the whole runtime
+surface:
+
+- close the Game task;
+- stop the process;
+- remove the VM session;
+- clear resident Game state and task-scoped lifecycle delivery;
+- restore Shell/Hub render ownership;
+- clear lifecycle audio pause state;
+- unbind the Game2D composer scene;
+- shut down cartridge-scoped asset manager state and physical banks;
+- emit explicit Hub/POS observability for manual kill.
+
+The Hub itself should emit a high-level action such as `KillResidentGame`; it
+should not know how to clean runtime subsystems.
+
+## Pitfalls
+
+- A UI-only kill that removes a task but leaves assets or composer binding alive
+  can still fail later when another Game renders.
+- A cleanup-only helper without an end-to-end Hub click test can miss the
+  interaction between hitbox, foreground ownership, render owner, and no-resume.
+- Hard-coded click coordinates in tests make the UI contract harder to maintain;
+  expose the layout hitbox when tests need to exercise it.
+
+## Takeaways
+
+- Visible system controls should produce system actions, not direct subsystem
+  mutation from UI code.
+- Manual kill and Game replacement are variants of the same resident Game
+  termination contract.
+- Cleanup tests should prove both logical state removal and visible-frame
+  behavior: the control appears before kill and disappears after kill.
+- "No resume after kill" is as important as "task closed" because resumability
+  is the user-facing state.

discussion/workflow/agendas/AGD-0044-systemos-cartridge-switch-orchestrator.md

@@ -1,178 +0,0 @@
----
-id: AGD-0044
-ticket: system-os-cartridge-switch-orchestrator
-title: SystemOS Cartridge Switch Orchestrator
-status: accepted
-created: 2026-07-03
-resolved:
-decision:
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Contexto
-
-A `AGD-0041` cobre o caso `Game -> Home/Shell -> mesmo Game`: o usuario sai do
-foreground do jogo, o SO assume a tela, Shell/Hub pode rodar, e depois o mesmo
-Game e retomado.
-
-Existe um segundo caso, diferente, que nao deve ser escondido dentro da
-`AGD-0041`: `Game A -> Home -> Game B`.
-
-Nesse fluxo, o usuario esta com um Game rodando, aperta Home, volta para o SO e
-pede para iniciar outro jogo. O SystemOS nao deve simplesmente chamar um loader
-por cima do estado atual. Ele precisa orquestrar a substituicao do app corrente:
-fechar ou descartar o Game residente, limpar estado cartridge-scoped, resolver o
-novo alvo, carregar o proximo cartucho e entrar no novo estado de firmware.
-
-Essa agenda tambem se relaciona com a `AGD-0003 / system-run-cart`: `run_cart`,
-se existir, nao e userland e nao e o orquestrador. O carregador de cartucho e
-apenas uma etapa dentro de uma transicao comandada pelo SystemOS.
-
-## Problema
-
-Sem um orquestrador explicito de troca de cartucho no SystemOS, a plataforma
-pode cair em estados incoerentes:
-
-- carregar um novo Game sem fechar corretamente o Game anterior;
-- reaproveitar estado VM, assets, input, audio, render ou telemetria do cartucho
-  anterior;
-- misturar boot direto por linha de comando com troca de app sob o SO;
-- deixar o loader decidir lifecycle, quando ele deveria apenas materializar o
-  cartucho alvo;
-- tentar implementar `Home -> outro Game` antes de existir o contrato de
-  foreground/pausa definido pela `AGD-0041`.
-
-## Pontos Criticos
-
-- Esta agenda deve ser executada depois da `AGD-0041`.
-- `Game -> Home -> mesmo Game` fica fora desta agenda.
-- O SystemOS deve ser a autoridade da troca entre cartuchos sob o SO.
-- O loader nao deve possuir politica de fechamento, pausa, foreground ou
-  cleanup.
-- Boot direto por CLI/debug continua sendo caminho separado e mais simples.
-- A troca para outro Game deve tratar falha de load sem deixar o sistema em
-  estado parcialmente substituido.
-- `.pmc`, catalogo completo e UX final de launcher continuam fora de escopo,
-  salvo se forem necessarios para definir o contrato minimo.
-
-## Opcoes
-
-### Opcao A - Adiar tudo para depois da AGD-0041
-
-- **Abordagem:** manter esta agenda como registro de escopo futuro; primeiro
-  fechar e implementar o contrato `Game -> Home -> mesmo Game`.
-- **Pro:** evita misturar pausa/resume com substituicao de cartucho; reduz risco
-  de reabrir arquitetura durante a `AGD-0041`.
-- **Contra:** a plataforma continua sem troca `Home -> outro Game` ate uma etapa
-  posterior.
-- **Manutenibilidade:** alta, porque cada agenda fecha um eixo de lifecycle.
-
-### Opcao B - Definir agora o contrato conceitual, implementar depois
-
-- **Abordagem:** fechar uma decisao curta ja dizendo que o orquestrador pertence
-  ao SystemOS, que `run_cart` nao e userland, e que a execucao depende da
-  `AGD-0041`; o plano de codigo fica para depois.
-- **Pro:** reduz ambiguidade enquanto trabalhamos na `AGD-0041`.
-- **Contra:** pode produzir uma decisao com pouca evidencia operacional antes
-  do contrato de foreground estar fechado.
-- **Manutenibilidade:** boa se a decisao for claramente marcada como dependente
-  da `AGD-0041`.
-
-### Opcao C - Implementar o orquestrador completo agora
-
-- **Abordagem:** tentar resolver `Game A -> Home -> Game B` antes ou junto da
-  `AGD-0041`.
-- **Pro:** ataca o fluxo final diretamente.
-- **Contra:** mistura pausa/resume, fechamento, cleanup, resolucao de alvo e
-  falha de load em uma unica frente; alto risco de contrato instavel.
-- **Manutenibilidade:** baixa para v1, porque a troca completa depende do
-  contrato de foreground ainda aberto.
-
-## Sugestao / Recomendacao
-
-`DSC-0041` foi fechada e o contrato de foreground/pausa/resume ja existe. A
-recomendacao agora deixa de ser adiar e passa a ser fechar uma decisao curta
-para o orquestrador de troca `Game A -> Home -> Game B`.
-
-O contrato sugerido e:
-
-- trocar para outro Game e uma substituicao controlada, nao uma pausa/resume;
-- o Game residente anterior e fechado/descartado;
-- a VM session do Game anterior e removida;
-- o novo Game sempre recebe uma VM session nova e zerada;
-- se o novo load falhar, o sistema volta ao Home/Hub com diagnostico e nao
-  tenta preservar o Game anterior em v1;
-- o loader continua sendo etapa interna, sem possuir politica de lifecycle;
-- a evidencia minima deve usar dois cartuchos distintos, incluindo um cartucho
-  simplista `dummy-boy` alem do stress test.
-
-## Perguntas em Aberto
-
-- [x] Depois da `AGD-0041`, qual estado representa um Game que sera descartado
-  em vez de retomado?
-  - Resposta: fechamento/encerramento controlado, nao `PausedSuspended`. O Game
-    anterior deixa de ser resident/resumable e sua VM session e removida.
-- [x] O fechamento do Game atual e observavel para o firmware/game, ou e uma
-  destruicao interna do SystemOS?
-  - Resposta: deve ser observavel como uma transicao de lifecycle/firmware, mas
-    nao cooperativo nem bloqueante para o Game. O SystemOS tem autoridade para
-    encerrar e descartar a sessao. Pode ser emitido um evento de encerramento
-    para permitir save/flush cooperativo quando existir esse mecanismo, mas a
-    troca nao deve depender da resposta do Game.
-- [x] Quais estados cartridge-scoped devem ser limpos antes do novo load: VM,
-  assets, FS handles, input, audio, render ownership, telemetry, logs?
-  - Resposta: a troca nao reaproveita VM. O Game anterior e encerrado, sua VM
-    session e descartada, e o novo Game recebe VM/session nova e zerada. Devem
-    ser limpos ou reatribuídos os estados cartridge-scoped ligados a VM,
-    handles abertos, input pendente/barreiras, audio do app, render ownership,
-    telemetry/debug/crash state do app. Logs historicos podem permanecer como
-    observabilidade.
-- [x] Se o novo cartucho falha ao carregar, o sistema volta ao Home, mostra uma
-  tela de erro, ou tenta preservar o Game anterior?
-  - Resposta: o Game anterior ja foi encerrado. Se o novo load falha, a sessao
-    parcial do novo Game e descartada e o sistema volta ao Home/Hub com
-    diagnostico. Preservar o Game anterior fica fora de escopo em v1.
-- [x] Como a resolucao do novo alvo e representada sem depender de catalogo
-  completo ou `.pmc`?
-  - Resposta: para o contrato minimo, o alvo pode ser um path/entrada ja
-    resolvido pelo Hub/game library atual. O contrato nao depende de `.pmc` nem
-    de catalogo final.
-- [x] Qual evidencia minima prova `Game A -> Home -> Game B` sem depender de UX
-  final de launcher?
-  - Resposta: criar um cartucho `dummy-boy` ao lado do stress test. O teste deve
-    provar `Stress -> Home -> Dummy Boy`, com troca de VM session, identidade de
-    cartridge distinta e render observavel do novo Game.
-
-## Criterio para Encerrar
-
-A agenda pode virar decisao quando:
-
-- a `AGD-0041` tiver fechado o contrato de foreground/pausa/resume;
-- estiver claro que o orquestrador pertence ao SystemOS;
-- `run_cart`/loader estiver limitado a etapa interna, nao userland;
-- existir regra para fechar/descartar o Game atual;
-- existir contrato de limpeza de estado cartridge-scoped;
-- existir politica para falha de carregamento do novo Game;
-- houver criterio de teste minimo para `Game A -> Home -> Game B`.
-
-## Discussao
-
-- 2026-07-03: Agenda criada a partir da separacao entre `AGD-0041`
-  (`Game -> Home -> mesmo Game`) e `AGD-0003` (`run_cart`/loader nao userland).
-  O novo escopo cobre a troca posterior `Game A -> Home -> Game B`, com
-  orquestracao pelo SystemOS depois que o contrato de foreground estiver
-  fechado.
-- 2026-07-05: Apos fechamento de `DSC-0041`, a discussao convergiu para troca
-  destrutiva simples em v1: ao iniciar outro Game, o Game residente anterior e
-  encerrado, sua VM session e removida, e o novo Game recebe VM session nova.
-  Falha de load volta ao Home/Hub com diagnostico. A evidencia minima deve
-  incluir um novo cartucho `dummy-boy` que desenha um quadrado com cores
-  oscilando, alem do stress test.
-- 2026-07-05: Refinamento: o encerramento do Game anterior pode emitir evento
-  cooperativo para save/flush, mas esse evento nao e uma permissao nem uma
-  barreira obrigatoria. O SystemOS continua com autoridade para concluir a troca
-  e remover a VM session anterior.
-
-## Resolution
-
-Pronta para virar decisao, pendente confirmacao explicita do usuario.

discussion/workflow/decisions/DEC-0039-systemos-game-cartridge-switch-orchestrator.md

@@ -1,174 +0,0 @@
----
-id: DEC-0039
-ticket: system-os-cartridge-switch-orchestrator
-title: SystemOS Game Cartridge Switch Orchestrator
-status: accepted
-created: 2026-07-05
-ref_agenda: AGD-0044
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Status
-
-Open for review.
-
-## Contexto
-
-`DEC-0037` fechou o contrato `Game -> Home/Shell -> mesmo Game`: o Game pode
-ficar residente, ser pausado/suspenso pelo SystemOS, e depois ser retomado.
-
-`DEC-0038` fechou o ownership de VM sessions: VM-backed mutable execution state
-pertence a sessoes de VM associadas a processos/tarefas, nao a uma VM global do
-firmware.
-
-Esta decision cobre outro fluxo: `Game A -> Home -> Game B`. Nesse caso, o
-usuario nao esta retomando o mesmo Game. O usuario esta escolhendo substituir o
-Game residente por outro cartucho. Essa substituicao precisa ser orquestrada
-pelo SystemOS, nao pelo loader e nao por userland.
-
-## Decisao
-
-PROMETEU MUST tratar `Game A -> Home -> Game B` como uma substituicao
-controlada de Game, nao como pause/resume.
-
-Quando o usuario escolher iniciar um Game diferente enquanto ja existe um Game
-residente, SystemOS MUST encerrar o Game residente anterior, remover sua
-resident state e descartar sua VM session antes de ativar o novo Game como
-resident/foreground.
-
-O Game anterior MAY receber um evento cooperativo de encerramento para permitir
-save/flush quando esse mecanismo existir. Esse evento MUST NOT ser uma
-permissao, veto ou barreira obrigatoria para a troca. SystemOS MUST manter
-autoridade para concluir a troca e remover a VM session anterior mesmo se o
-Game nao reagir.
-
-O novo Game MUST receber uma VM session nova e zerada. A troca MUST NOT
-reutilizar a VM session, PC, stack, heap, globals, open handles, cartridge
-identity, lifecycle state, debug state ou runtime state do Game anterior.
-
-O loader/materializador de cartridge MUST permanecer uma etapa interna de
-carregamento. Ele MUST NOT possuir politica de lifecycle, foreground,
-close/discard, cleanup ou recuperacao de falha.
-
-Se o novo cartucho falhar ao carregar, SystemOS MUST descartar qualquer session
-parcial ou estado cartridge-scoped parcial do novo Game e retornar ao Home/Hub
-com diagnostico. V1 MUST NOT tentar preservar ou restaurar o Game anterior
-depois que a troca tiver comecado.
-
-Boot direto por CLI/debug permanece um caminho separado e mais simples. Esta
-decision governa troca de Game sob SystemOS depois que o usuario retorna ao
-Home/Hub.
-
-A evidencia minima de implementacao MUST incluir dois test cartridges
-distintos: o stress cartridge existente e um novo cartridge `dummy-boy`.
-`dummy-boy` MUST renderizar um quadrado visualmente distinto com cor oscilante
-para que os testes provem que o segundo Game, e nao um frame/session anterior
-stale, esta ativo.
-
-## Rationale
-
-Trying to preserve Game A while loading Game B would turn the switch into a
-transactional snapshot/rollback problem. That is not needed for v1 and would
-pull in VM snapshot correctness, open handle restoration, assets, render
-ownership rollback, audio rollback, input state, debugger state, and telemetry
-rollback.
-
-The simpler and safer v1 contract is destructive replacement:
-
-1. the user requests another Game;
-2. SystemOS ends the previous resident Game;
-3. SystemOS removes its VM session and cartridge-scoped runtime state;
-4. SystemOS attempts to load the new Game into a fresh VM session;
-5. success enters the new Game;
-6. failure returns to Home/Hub with diagnostic.
-
-This aligns with `DEC-0037` because pause/suspend remains the same-Game resume
-flow. It aligns with `DEC-0038` because VM identity is session-owned and each
-Game receives a distinct VM session.
-
-## Invariantes / Contrato
-
-- SystemOS is the authority for switching from one Game cartridge to another
-  under Home/Hub.
-- `Game -> Home -> same Game` is pause/resume and remains governed by
-  `DEC-0037`.
-- `Game A -> Home -> Game B` is destructive replacement and is governed by this
-  decision.
-- A Game that is being replaced MUST stop being resident/resumable.
-- The previous Game VM session MUST be removed before the new Game becomes the
-  active resident/foreground Game.
-- A cooperative close/terminate/save event MAY be delivered to the previous
-  Game, but it MUST NOT block replacement.
-- The new Game MUST get a fresh VM session.
-- The new Game MUST NOT inherit VM execution state, open handles, lifecycle
-  delivery state, cartridge identity, debug state, telemetry state, or crash
-  state from the previous Game.
-- Render ownership MUST transition through SystemOS ownership policy and stale
-  submissions from the previous Game MUST NOT be presented after the switch.
-- Input pending/barrier state MUST be cleared or made safe across the switch.
-- App audio from the previous Game MUST be stopped or detached from the active
-  app before the new Game becomes foreground.
-- Logs MAY remain as historical observability; they are not cartridge execution
-  state.
-- If new Game load fails, Home/Hub is the recovery state for v1.
-- V1 does not preserve, restore, or rollback to the previous Game after a
-  switch begins.
-- The launcher target MAY be a path or already-resolved game-library entry for
-  v1. `.pmc` and final catalog UX are out of scope.
-- `run_cart`, if retained, is not a userland command and not the switch
-  orchestrator.
-
-## Impactos
-
-- **Runtime / SystemOS:** needs an explicit Game switch orchestration path that
-  closes/removes the current resident Game session before loading the next Game.
-- **Lifecycle:** needs a controlled replacement transition distinct from
-  pause/suspend/resume.
-- **VM sessions:** previous Game session removal and new Game session creation
-  are mandatory switch steps.
-- **Firmware:** should observe macro states such as Home, loading, load failure,
-  and GameRunning, but should not own switch policy.
-- **Hub / launcher:** should request a switch through SystemOS using a resolved
-  target; it should not call a loader directly as lifecycle authority.
-- **Loader:** remains a materialization step and returns success/failure without
-  owning cleanup policy.
-- **Renderer:** render ownership/stale submission invalidation must prove the
-  new Game owns current presentation after success.
-- **Input/audio:** previous Game input/audio must not leak into the new Game.
-- **Tests:** need a second visually distinct test cartridge, `dummy-boy`, to
-  prove Game identity and render transition.
-
-## Alternativas Descartadas
-
-- **Preserve Game A until Game B loads successfully:** rejected for v1 because it
-  requires rollback semantics across VM, assets, handles, render ownership,
-  input, audio, debugger, and telemetry.
-- **Treat Game A -> Game B as pause/resume:** rejected because a different Game
-  should not inherit resumable state from the previous Game.
-- **Let the loader close the previous Game:** rejected because loader/materializer
-  should not own lifecycle policy.
-- **Reuse the previous VM session for the new Game:** rejected because it
-  violates VM session ownership and risks state leakage.
-- **Depend on `.pmc` or final catalog UX now:** rejected because the lifecycle
-  contract can be validated using path/game-library targets first.
-
-## Referencias
-
-- Source agenda: `AGD-0044`
-- Foreground stack and Game pause contract: `DEC-0037`
-- VM session ownership for VM-backed processes: `DEC-0038`
-- SystemOS lifecycle/process/task authority: `DSC-0032`
-- Launch authority lesson: `LSN-0051`
-- Foreground/session ownership lesson: `LSN-0052`
-
-## Propagacao Necessaria
-
-- Add/update runtime spec for Game cartridge switching under SystemOS.
-- Add implementation plans for:
-  - SystemOS switch orchestration;
-  - resident Game termination/session removal;
-  - fresh session load for the new Game;
-  - failure recovery to Home/Hub;
-  - `dummy-boy` test cartridge;
-  - end-to-end `Stress -> Home -> Dummy Boy` validation.
-- Ensure host/debug direct boot remains separate from SystemOS Game switch.

discussion/workflow/plans/PLN-0157-introduce-systemos-game-switch-target-contract.md

@@ -1,86 +0,0 @@
----
-id: PLN-0157
-ticket: system-os-cartridge-switch-orchestrator
-title: Introduce SystemOS Game Switch Target Contract
-status: done
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 requires Game-to-Game switching under Home/Hub to be owned by SystemOS.
-Before destructive replacement can be implemented, Hub/Firmware/SystemOS need a
-small explicit contract for "launch this resolved Game target as a replacement"
-that is separate from direct boot and from loader internals.
-
-## Objective
-
-Introduce a SystemOS-owned Game switch request/target abstraction that can carry
-a resolved cartridge path or game-library entry from Hub/Home into the switch
-orchestrator without making the loader or userland the lifecycle authority.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Builds on DEC-0037 and DEC-0038 as already implemented.
-- Must be implemented before PLN-0158, PLN-0159, and PLN-0161.
-
-## Scope
-
-- Define a minimal Game switch target type, such as `GameSwitchTarget` or
-  `CartridgeLaunchTarget`, in the SystemOS/Firmware boundary.
-- Route Hub game-library launch actions through that target contract instead of
-  treating a path as an implicit lifecycle operation.
-- Keep direct boot/debug boot paths separate from SystemOS Game switching.
-- Add tests proving the target preserves cartridge identity/path without
-  starting lifecycle replacement by itself.
-
-## Non-Goals
-
-- Do not implement destructive replacement in this plan.
-- Do not add `.pmc`, final catalog UX, or a new launcher UI.
-- Do not change direct CLI/debug boot behavior.
-- Do not add background execution.
-
-## Execution Method
-
-1. Inspect `crates/console/prometeu-system/src/services/game_library.rs`,
-   `crates/console/prometeu-system/src/programs/prometeu_hub/prometeu_hub.rs`,
-   and `crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs`.
-2. Add a minimal launch target model at the SystemOS/Firmware boundary:
-   - resolved cartridge path;
-   - optional app_id/title metadata if already available;
-   - no loader-owned lifecycle policy.
-3. Update Hub action plumbing so `SystemProfileAction::LaunchGame` carries the
-   resolved target type or maps immediately into it at the firmware boundary.
-4. Add a placeholder SystemOS/Firmware entry point for Game switching that
-   accepts the target but still delegates to the existing load path until
-   PLN-0158 changes replacement behavior.
-5. Add unit tests for target construction and path propagation.
-6. Keep direct `BootTarget::Cartridge` behavior unchanged.
-
-## Acceptance Criteria
-
-- There is an explicit type or function contract representing a resolved
-  SystemOS Game switch target.
-- Hub/Home no longer treats a raw path as lifecycle authority.
-- The loader remains a materialization step, not the switch orchestrator.
-- Direct boot/debug boot code paths remain separate and behaviorally unchanged.
-- Tests prove target identity is carried without implicitly closing or loading a
-  Game.
-
-## Tests
-
-- `cargo test -p prometeu-system`
-- `cargo test -p prometeu-firmware`
-- `cargo test -p prometeu-host-desktop-winit`
-- `cargo clippy -p prometeu-system -p prometeu-firmware -p prometeu-host-desktop-winit --all-targets -- -D warnings`
-
-## Affected Artifacts
-
-- `crates/console/prometeu-system/src/services/game_library.rs`
-- `crates/console/prometeu-system/src/programs/prometeu_hub/prometeu_hub.rs`
-- `crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs`
-- `crates/console/prometeu-firmware/src/firmware/firmware.rs`

discussion/workflow/plans/PLN-0158-terminate-resident-game-before-switching-cartridges.md

@@ -1,98 +0,0 @@
----
-id: PLN-0158
-ticket: system-os-cartridge-switch-orchestrator
-title: Terminate Resident Game Before Switching Cartridges
-status: done
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 defines `Game A -> Home -> Game B` as destructive replacement. The
-current same-Game resume flow keeps the resident Game session alive; switching
-to a different Game must instead close/remove that resident session and create a
-fresh session for the new Game.
-
-## Objective
-
-Implement the SystemOS lifecycle/session operation that terminates the current
-resident Game before loading a different Game cartridge.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Requires PLN-0157 target contract.
-- Should be implemented before PLN-0159 and PLN-0161.
-
-## Scope
-
-- Add a controlled resident Game termination/replacement operation to SystemOS
-  lifecycle/session services.
-- Optionally emit a cooperative terminate/close/save lifecycle event when the
-  current event model can carry it, but do not block replacement on it.
-- Remove the previous Game from resident/resumable state.
-- Remove the previous Game VM session before activating the new Game.
-- Clear or reassign app-scoped state that cannot leak into the new Game:
-  session VM, open handles, pending lifecycle state, input barrier/pending
-  input, audio active app state, render ownership, telemetry/debug/crash state.
-
-## Non-Goals
-
-- Do not preserve Game A for rollback.
-- Do not implement failed-load recovery beyond surfacing errors; that is
-  PLN-0159.
-- Do not add background execution or multiple resident Games.
-- Do not build final launcher UX.
-
-## Execution Method
-
-1. Inspect lifecycle/session state in:
-   - `crates/console/prometeu-system/src/os/lifecycle.rs`;
-   - `crates/console/prometeu-system/src/os/facades/sessions.rs`;
-   - `crates/console/prometeu-system/src/services/foreground`;
-   - `crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs`;
-   - `crates/console/prometeu-firmware/src/firmware/firmware_step_load_cartridge.rs`.
-2. Add a `replace_resident_game` or equivalent operation that:
-   - finds the current resident Game;
-   - marks its task/process closed or stopped according to existing lifecycle
-     semantics;
-   - removes the resident Game entry from foreground stack/lifecycle state;
-   - removes its VM session.
-3. Ensure same-Game resume still bypasses replacement and remains governed by
-   DEC-0037.
-4. Update game launch from Home so launching a different app_id triggers
-   replacement before load.
-5. Ensure render ownership transitions away from the old Game before the new
-   Game becomes foreground.
-6. Add focused tests for resident Game termination and session removal.
-
-## Acceptance Criteria
-
-- Launching a different Game from Home closes/removes the resident Game rather
-  than resuming it.
-- The previous Game VM session is absent before the new Game is made active.
-- Same-Game selection still resumes the existing resident Game.
-- A cooperative close/terminate event, if added, is non-blocking.
-- No previous Game VM, handle, lifecycle, render, or debug state is reused by
-  the new Game.
-
-## Tests
-
-- `cargo test -p prometeu-system`
-- `cargo test -p prometeu-firmware`
-- `cargo clippy -p prometeu-system -p prometeu-firmware --all-targets -- -D warnings`
-- Add tests for:
-  - different Game launch removes previous resident session;
-  - same Game launch resumes existing resident session;
-  - old Game task/process state is closed/stopped;
-  - old Game session cannot be resolved after replacement starts.
-
-## Affected Artifacts
-
-- `crates/console/prometeu-system/src/os/lifecycle.rs`
-- `crates/console/prometeu-system/src/os/facades/sessions.rs`
-- `crates/console/prometeu-system/src/services/foreground`
-- `crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs`
-- `crates/console/prometeu-firmware/src/firmware/firmware_step_load_cartridge.rs`

discussion/workflow/plans/PLN-0159-recover-failed-game-switches-back-to-home.md

@@ -1,86 +0,0 @@
----
-id: PLN-0159
-ticket: system-os-cartridge-switch-orchestrator
-title: Recover Failed Game Switches Back To Home
-status: open
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 rejects preserving Game A after a switch begins. If Game B fails to
-load, the system must discard partial Game B state and return to Home/Hub with a
-diagnostic, not attempt rollback to Game A.
-
-## Objective
-
-Implement controlled failed-switch recovery to Home/Hub after destructive Game
-replacement begins.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Requires PLN-0157 target contract.
-- Requires PLN-0158 resident Game termination/session removal.
-
-## Scope
-
-- Detect load/init failure while switching to a different Game.
-- Discard any partial new Game task/session/window/render/input/audio state.
-- Return firmware/SystemOS to Home/Hub.
-- Log or expose a diagnostic that Home can surface or tests can assert.
-- Ensure previous Game is not restored after switch failure.
-
-## Non-Goals
-
-- Do not implement transactional rollback.
-- Do not preserve the previous Game after switch begins.
-- Do not design final user-facing error UI.
-- Do not change direct boot failure behavior unless needed to keep paths
-  separate.
-
-## Execution Method
-
-1. Inspect existing load failure flow in
-   `crates/console/prometeu-firmware/src/firmware/firmware_step_load_cartridge.rs`.
-2. Add a switch-specific failure outcome or context flag that distinguishes
-   SystemOS Game switching from direct boot load.
-3. On switch load failure:
-   - remove partial new VM session/task/process if created;
-   - clear partial cartridge-scoped state;
-   - transition to `HubHome` instead of app crash when appropriate for switch
-     recovery;
-   - log a diagnostic containing target identity/path and failure summary.
-4. Preserve existing direct boot and explicit load failure tests unless a direct
-   boot path intentionally still goes to crash.
-5. Add tests for bad Game B after Game A was already terminated.
-
-## Acceptance Criteria
-
-- Failed `Game A -> Home -> Broken Game B` returns to Home/Hub.
-- Previous Game A is not resident, resumable, or restored.
-- Partial Game B VM session/task/process state is removed or closed.
-- A diagnostic is logged or otherwise observable.
-- Existing direct boot/debug boot failure semantics remain separate.
-
-## Tests
-
-- `cargo test -p prometeu-firmware`
-- `cargo test -p prometeu-system`
-- `cargo test -p prometeu-host-desktop-winit`
-- `cargo clippy -p prometeu-system -p prometeu-firmware -p prometeu-host-desktop-winit --all-targets -- -D warnings`
-- Add tests for:
-  - switch failure returns Home;
-  - old Game not restored;
-  - partial new session cleanup;
-  - direct boot failure path remains unchanged.
-
-## Affected Artifacts
-
-- `crates/console/prometeu-firmware/src/firmware/firmware_step_load_cartridge.rs`
-- `crates/console/prometeu-firmware/src/firmware/firmware_step_hub_home.rs`
-- `crates/console/prometeu-firmware/src/firmware/firmware.rs`
-- `crates/console/prometeu-system/src/os/facades/sessions.rs`
-- `crates/console/prometeu-system/src/os/lifecycle.rs`

discussion/workflow/plans/PLN-0160-add-dummy-boy-visual-switch-test-cartridge.md

@@ -1,90 +0,0 @@
----
-id: PLN-0160
-ticket: system-os-cartridge-switch-orchestrator
-title: Add Dummy Boy Visual Switch Test Cartridge
-status: open
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 requires minimum evidence using two distinct test cartridges. The
-existing stress cartridge proves execution/logging but is not visually distinct
-enough for switch validation. A second cartridge, `dummy-boy`, must render an
-oscillating-color square.
-
-## Objective
-
-Add a simple `test-cartridges/dummy-boy` cartridge that renders a visible square
-with changing colors so Game switching can prove visual/session identity.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Can be implemented independently of PLN-0157 through PLN-0159.
-- Required before PLN-0161 end-to-end validation.
-
-## Scope
-
-- Add `test-cartridges/dummy-boy/manifest.json`.
-- Generate or add `test-cartridges/dummy-boy/program.pbx`.
-- Add empty or minimal assets payload if the loader requires `assets.pa`.
-- Implement Dummy Boy behavior:
-  - Game cartridge identity distinct from stress;
-  - deterministic visible square;
-  - color oscillates across frames;
-  - no dependency on final launcher UX.
-- Add build/generation documentation or tests so the cartridge can be
-  regenerated safely if needed.
-
-## Non-Goals
-
-- Do not add final game content.
-- Do not add `.pmc`.
-- Do not depend on host screenshots for the first validation unless an existing
-  harness already supports it.
-- Do not change stress cartridge behavior.
-
-## Execution Method
-
-1. Inspect the stress cartridge and any PBX generator tooling:
-   - `test-cartridges/stress-console`;
-   - `crates/tools/pbxgen-stress`;
-   - bytecode assembler helpers in `crates/console/prometeu-bytecode`.
-2. Choose the smallest maintainable generator path:
-   - extend existing PBX generator if appropriate; or
-   - add a focused `pbxgen-dummy-boy` tool; or
-   - add deterministic generated PBX with source instructions.
-3. Create `manifest.json` with unique `app_id`, title `Dummy Boy`, Game mode,
-   and version.
-4. Generate `program.pbx` that renders the square and advances color over
-   frames.
-5. Add tests or smoke checks that the cartridge is discoverable by games-root
-   discovery.
-
-## Acceptance Criteria
-
-- `test-cartridges/dummy-boy` exists and loads as a Game cartridge.
-- Dummy Boy has a unique `app_id` and title distinct from Stress.
-- Dummy Boy renders a visible square.
-- Square color changes deterministically over time.
-- Games-root discovery sees both Stress and Dummy Boy.
-- Existing stress cartridge remains unchanged.
-
-## Tests
-
-- `cargo test -p prometeu-hal`
-- `cargo test -p prometeu-system`
-- `cargo test -p prometeu-firmware`
-- Run any cartridge generator tests added by this plan.
-- Add or update tests for games-root discovery including Dummy Boy.
-
-## Affected Artifacts
-
-- `test-cartridges/dummy-boy/manifest.json`
-- `test-cartridges/dummy-boy/program.pbx`
-- `test-cartridges/dummy-boy/assets.pa` if required
-- `crates/tools/*` cartridge generator tooling if needed
-- `crates/console/prometeu-system/src/services/game_library.rs` tests if needed

discussion/workflow/plans/PLN-0161-validate-stress-to-dummy-boy-game-switch-end-to-end.md

@@ -1,93 +0,0 @@
----
-id: PLN-0161
-ticket: system-os-cartridge-switch-orchestrator
-title: Validate Stress To Dummy Boy Game Switch End To End
-status: open
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 requires proof that `Game A -> Home -> Game B` creates a fresh Game
-session and does not present stale state from Game A. The minimum evidence is
-switching from Stress to Dummy Boy.
-
-## Objective
-
-Add end-to-end validation for `Stress -> Home -> Dummy Boy` through the real
-Hub/Home flow, proving lifecycle, VM session, cartridge identity, and render
-ownership switch correctly.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Requires PLN-0157 target contract.
-- Requires PLN-0158 destructive replacement.
-- Requires PLN-0159 failed-switch recovery for negative path assertions.
-- Requires PLN-0160 Dummy Boy cartridge.
-
-## Scope
-
-- Add firmware/system tests that drive:
-  - launch Stress from games root;
-  - request Home;
-  - launch Dummy Boy;
-  - assert Stress session is gone;
-  - assert Dummy Boy session is active;
-  - assert cartridge identity and render ownership belong to Dummy Boy.
-- Add a negative end-to-end test for broken Game B returning to Home if not
-  already covered by PLN-0159.
-- Use existing test platform/render submission inspection where possible.
-
-## Non-Goals
-
-- Do not require final launcher UX.
-- Do not add screenshot-based host automation unless existing test utilities
-  make it cheap and deterministic.
-- Do not implement additional Game-to-Game variants beyond Stress to Dummy Boy.
-
-## Execution Method
-
-1. Inspect existing firmware tests in
-   `crates/console/prometeu-firmware/src/firmware/firmware.rs`.
-2. Reuse existing `TestGameRoot` or games-root helpers to expose Stress and
-   Dummy Boy.
-3. Drive input through Hub/Home selection rather than calling cartridge load
-   directly when possible.
-4. Assert lifecycle/session invariants:
-   - old task closed/stopped;
-   - old VM session removed;
-   - new VM session created;
-   - foreground owner is new Game;
-   - current cartridge identity is Dummy Boy.
-5. Assert render invariants:
-   - render ownership epoch belongs to Dummy Boy app identity;
-   - stale Stress submissions are not accepted after switch;
-   - latest observable Game frame comes from Dummy Boy when render inspection is
-     available.
-6. Add a focused test for failure path if missing after PLN-0159.
-
-## Acceptance Criteria
-
-- End-to-end test proves Stress can be replaced by Dummy Boy from Home.
-- Stress is not resumable after switching to Dummy Boy.
-- Dummy Boy receives a fresh VM session.
-- Cartridge identity and active render ownership are Dummy Boy after switch.
-- Failure path returns Home and does not restore Stress.
-- Tests are deterministic and do not rely on manual host interaction.
-
-## Tests
-
-- `cargo test -p prometeu-firmware`
-- `cargo test -p prometeu-system`
-- `cargo test -p prometeu-host-desktop-winit`
-- `cargo clippy -p prometeu-system -p prometeu-firmware -p prometeu-host-desktop-winit --all-targets -- -D warnings`
-
-## Affected Artifacts
-
-- `crates/console/prometeu-firmware/src/firmware/firmware.rs`
-- `crates/console/prometeu-system/src/services/game_library.rs`
-- `test-cartridges/dummy-boy`
-- Host/render test utilities if needed

discussion/workflow/plans/PLN-0162-specify-game-switch-contract-and-direct-boot-separation.md

@@ -1,93 +0,0 @@
----
-id: PLN-0162
-ticket: system-os-cartridge-switch-orchestrator
-title: Specify Game Switch Contract And Direct Boot Separation
-status: open
-created: 2026-07-05
-ref_decisions: [DEC-0039]
-tags: [runtime, os, lifecycle, game, cartridge, architecture]
----
-
-## Briefing
-
-DEC-0039 must be reflected in the canonical runtime specs after the operational
-contract is implemented or alongside implementation. The spec must distinguish
-same-Game resume, Game replacement under SystemOS, and direct boot/debug boot.
-
-## Objective
-
-Update the canonical runtime documentation to describe SystemOS Game cartridge
-switching and to keep direct boot/debug boot separate from Home/Hub-driven Game
-replacement.
-
-## Dependencies
-
-- Source decision: DEC-0039.
-- Can be implemented before code if the spec is written as intended behavior.
-- Should be reconciled after PLN-0157 through PLN-0161 if implementation names
-  differ from initial plan names.
-
-## Scope
-
-- Update relevant files under `docs/specs/runtime/`, especially:
-  - `12-firmware-pos-and-prometeuhub.md`;
-  - `13-cartridge.md`;
-  - `14-boot-profiles.md`;
-  - `09-events-and-concurrency.md` if lifecycle events need mention;
-  - `10-debug-inspection-and-profiling.md` if debugger separation needs note.
-- Document:
-  - SystemOS authority for Game switching;
-  - destructive replacement semantics;
-  - optional non-blocking terminate/save event;
-  - fresh VM session for new Game;
-  - failed switch recovery to Home/Hub;
-  - direct boot/debug boot separation;
-  - test cartridge evidence requirement.
-
-## Non-Goals
-
-- Do not document `.pmc` or final catalog UX as required.
-- Do not specify background execution.
-- Do not revise DEC-0037 or DEC-0038 semantics.
-- Do not write lesson material; housekeeping will decide lessons after
-  execution.
-
-## Execution Method
-
-1. Read the runtime spec files listed in scope.
-2. Add a Game switching section in the most appropriate canonical spec file.
-3. Cross-reference existing Home/Hub, cartridge, boot profile, and debug boot
-   sections.
-4. Ensure language is English and normative enough for future implementers:
-   `MUST`, `MUST NOT`, `MAY`, `SHOULD`.
-5. Verify no non-English agenda language leaks into specs.
-6. Run docs grep checks for the newly introduced terms.
-
-## Acceptance Criteria
-
-- Specs explicitly distinguish:
-  - same-Game pause/resume;
-  - Game A to Game B destructive replacement;
-  - direct boot/debug boot.
-- Specs state that SystemOS owns Game switching policy.
-- Specs state that a new Game gets a fresh VM session.
-- Specs state that failed switch returns Home/Hub and does not restore the old
-  Game in v1.
-- Specs mention Dummy Boy or equivalent two-cartridge evidence only as test
-  evidence, not as runtime feature.
-- Documentation is English.
-
-## Tests
-
-- `rg -n "Game switch|destructive replacement|direct boot|Dummy Boy|VM session" docs/specs/runtime`
-- `discussion validate`
-- Run code tests only if this plan is implemented together with code changes:
-  `cargo test -p prometeu-system -p prometeu-firmware`
-
-## Affected Artifacts
-
-- `docs/specs/runtime/12-firmware-pos-and-prometeuhub.md`
-- `docs/specs/runtime/13-cartridge.md`
-- `docs/specs/runtime/14-boot-profiles.md`
-- `docs/specs/runtime/09-events-and-concurrency.md`
-- `docs/specs/runtime/10-debug-inspection-and-profiling.md`

docs/specs/runtime/09-events-and-concurrency.md

@@ -128,6 +128,11 @@ SystemOS resume request
 scheduler/runtime state. A Game may observe pause/resume, but it must not
 control whether SystemOS suspends or resumes the VM.
 
+When SystemOS replaces one Game with another from Home, the old Game MAY receive
+a cooperative terminate/save lifecycle event if the runtime supports such an
+event. That event is non-blocking in v1. SystemOS remains authoritative and may
+close the old Game task/session without guest acknowledgement.
+
 Pause budgets are measured in deterministic machine units, not host wall-clock
 time. A suspended Game receives no normal gameplay ticks, no normal Game input,
 and no frame pacing. Real background execution is outside the v1 foreground
@@ -163,6 +168,20 @@ requires it. Transient VM handles, open files, lifecycle delivery queues, and
 staging state are session-scoped unless another spec explicitly makes them
 durable app data.
 
+During destructive Game replacement, the old Game VM session MUST be removed
+from execution eligibility and resumable state before the new Game becomes the
+foreground Game. The new Game MUST receive a fresh VM session. Failure while
+loading or initializing the replacement Game MUST return the machine to
+Hub/Home and MUST NOT restore the previous Game in v1.
+
+Manual Hub termination of a suspended resident Game has the same session
+removal authority as destructive Game replacement, except that no replacement
+Game is started. SystemOS MUST remove the Game from execution eligibility and
+resumable state, close its task, stop its process, remove its VM session, clear
+task-scoped pending lifecycle delivery, and keep Hub/Home as the foreground
+owner. After manual Hub termination, resume queries MUST report no resident
+Game. A later launch of the same cartridge is a fresh Game session.
+
 ## 9 Render Worker Concurrency
 
 The render worker is not a machine-visible event source and does not introduce

docs/specs/runtime/10-debug-inspection-and-profiling.md

@@ -44,6 +44,11 @@ PROMETEU operates in three main modes:
 
 No mode alters the logical result of the program.
 
+Debug boot is a host-selected direct cartridge boot profile. It follows the same
+cartridge/app-mode resolution path as direct boot and is separate from
+Home-driven Game switching. Debug boot MUST NOT be modeled as a guest-visible
+Game switch request and MUST NOT reuse a Home switch failure-recovery contract.
+
 ## 3 Execution Control
 
 ### 3.1 Pause and Resume

docs/specs/runtime/12-firmware-pos-and-prometeuhub.md

@@ -43,6 +43,9 @@ The VM does not own the machine lifecycle. Firmware does.
   Game directory cartridges.
 - **Library entry**: an internal catalog record retained by Hub/SystemOS for a
   discovered cartridge.
+- **Game switch target**: a SystemOS-owned launch target derived from a library
+  entry. It carries the cartridge path plus resolved identity such as `app_id`,
+  `title`, and `app_version`.
 - **Foreground visual owner**: the single machine owner whose visual output may
   be presented at a given time.
 - **Paused**: a Game-visible lifecycle event/state. The Game may observe it and
@@ -52,6 +55,8 @@ The VM does not own the machine lifecycle. Firmware does.
   frame pacing.
 - **VM session**: the POS-owned mutable execution context for one VM-backed
   process. It contains the VM instance and per-session runtime state.
+- **Hub resident Game kill control**: a Hub/Home affordance that terminates the
+  current resident Game instead of resuming it.
 
 ## 3 POS Responsibilities
 
@@ -86,6 +91,8 @@ PrometeuHub is responsible for:
 - presenting the host-provided local games library when `--games-root <dir>` is
   configured;
 - emitting system-owned launch actions for selected Home entries.
+- presenting a resident Game kill control while Hub/Home owns foreground and a
+  Game is resident/suspended.
 
 The Hub does not execute bytecode directly. It always delegates execution setup to POS.
 
@@ -216,6 +223,17 @@ It preserves Game VM state but is not execution-eligible except for the bounded
 pause handoff and later foreground resume. A VM-backed Shell has a separate VM
 session. A native Shell has no VM session.
 
+When Hub/Home is foreground and a Game cartridge remains resident/suspended,
+PrometeuHub MUST render a red control in the bottom-right of the Hub viewport.
+The control MUST display only the resident Game title. It MUST NOT be rendered
+for no resident Game, Shell tasks, System tasks, or native Shell tasks.
+
+Clicking the Hub resident Game kill control is a system-owned immediate
+termination request. Firmware MUST keep the user in Hub/Home, MUST NOT ask for
+confirmation in v1, and MUST NOT resume the killed Game on subsequent Home
+actions. The control MUST disappear on the next Hub frame after the resident
+Game is no longer present.
+
 ## 8 Cartridge Load Flow
 
 Current high-level flow:
@@ -231,11 +249,51 @@ Current high-level flow:
 If VM initialization fails, firmware transitions to the crash path.
 
 For v1, POS must enforce at most one resident Game session. Selecting the same
-resident Game from Home resumes that session. Selecting a different Game while a
+resident Game from Home resumes that session. Selecting a different Game from
-resident Game exists is outside the v1 foreground contract and must not create a
+Home is a SystemOS-owned Game switch and MUST be destructive replacement:
-second resident Game session. VM-backed Shell loading creates a distinct Shell
+
+```text
+Game A resident
+    -> Hub/Home selected Game B with different app_id
+    -> SystemOS terminates Game A resident task/session
+    -> SystemOS removes Game A from resumable state
+    -> firmware loads Game B through LoadCartridge
+    -> Game B receives a fresh VM session
+```
+
+SystemOS MUST NOT create a second resident Game session. SystemOS MUST NOT
+reuse the old Game VM session, transient VM handles, pending lifecycle delivery
+state, render ownership, debug pause state, or crash/debug runtime state for the
+new Game. Durable app data remains governed by the relevant storage specs and
+may still be keyed by `app_id`.
+
+SystemOS MAY emit a cooperative non-blocking terminate/save lifecycle event
+before closing the old Game when such an event exists. Replacement MUST NOT
+block on that event in v1. VM-backed Shell loading creates a distinct Shell
 session and must not overwrite resident Game VM state.
 
+Manual Hub resident Game kill and destructive different-Game replacement MUST
+share the canonical resident-Game termination path. That path MUST:
+
+- close the resident Game task;
+- mark its process stopped;
+- remove its VM session;
+- clear resident Game state and pending Game lifecycle delivery for that task;
+- keep or return foreground ownership to Hub/Home;
+- transition render ownership to Shell/Hub (`AppMode::Shell`, `app_id = 0`);
+- clear the Game lifecycle audio pause state;
+- unbind the Game2D frame composer scene;
+- shut down cartridge-scoped asset manager state, including slot identity and
+  physical glyph/scene/sound banks.
+
+After this operation, the killed Game MUST NOT be resumable. Launching that
+same Game again from Home is a fresh cartridge load and a fresh VM session.
+Manual Hub kill MUST emit an INFO Hub log with the message shape:
+
+```text
+Resident game killed from Hub: <title>
+```
+
 POS selects the cartridge and its execution context, but the cartridge's initial callable is not chosen by firmware metadata. Execution starts from the cartridge boot protocol defined in [`13-cartridge.md`](13-cartridge.md), currently `func_id = 0`.
 
 When Home launches a discovered Game entry, the request is a system-owned action
@@ -248,6 +306,16 @@ If the selected cartridge cannot be loaded, firmware must leave or return the
 machine in the Hub/Home flow and record the failure through diagnostics or
 logging. A polished Home error surface is not required by v1.
 
+If a destructive Game switch has already begun and the new Game fails to load or
+initialize, firmware MUST return to Hub/Home, MUST discard any partial new Game
+task/session/window/render/input/audio state, and MUST NOT restore the previous
+Game. Direct boot and debug boot failures remain governed by the boot profile
+that requested them and may still transition to the crash path.
+
+Switch validation MUST include two distinct Game cartridges. The current
+repository evidence uses `Stress Console` and `Dummy Boy`; those cartridges are
+test evidence, not required runtime features.
+
 ## 9 Firmware States
 
 The current firmware state model includes:
@@ -310,6 +378,9 @@ Expected behavior:
   resident Game session;
 - returning to the same Game resumes it through the foreground lifecycle and
   waits for current-epoch Game rendering before visual Game presentation.
+- clicking the red bottom-right resident Game kill control terminates the
+  resident Game, keeps Home foreground, clears runtime/cartridge residue, and
+  removes the resume path.
 
 ## 13 Relationship to Other Specs
 

docs/specs/runtime/13-cartridge.md

@@ -186,6 +186,9 @@ For the v1 Home games library:
 - the manifest must declare `app_mode: "Game"`;
 - the library retains the loaded manifest data, `title`, `app_id`,
   `app_version`, the internal cartridge path, and discovery metadata;
+- the library entry identity is the input to the SystemOS Game switch target;
+- `app_id` is the v1 identity used to distinguish same-Game resume from
+  different-Game destructive replacement;
 - invalid candidates are logged or reported as diagnostics and omitted from the
   Home list;
 - valid non-Game cartridges are omitted from the Game library.
@@ -193,6 +196,11 @@ For the v1 Home games library:
 Discovery reads metadata for cataloging. It does not replace the normal
 cartridge loader used when firmware starts the selected cartridge.
 
+Selecting a discovered Game from Home is not cartridge self-execution and is not
+guest-controlled. The cartridge path is consumed by firmware/SystemOS, which
+owns same-Game resume, different-Game replacement, failure recovery, and VM
+session creation policy.
+
 ### Packaged `.pmc` form
 
 This form is recognized conceptually by the loader boundary, but its actual load path is not implemented yet.

docs/specs/runtime/14-boot-profiles.md

@@ -97,9 +97,11 @@ The v1 games root contract is:
   and transitions through `LoadCartridge`;
 - launch failure leaves or returns the machine to Home and records an error.
 
-Game-to-game switching after a game is already active is not part of this boot
+Game-to-game switching after a game is already active is not a boot profile.
-profile. That orchestration belongs to the foreground/home and cartridge switch
+That orchestration belongs to the foreground/home and cartridge switch
-contracts.
+contracts. In that path, SystemOS owns the switch policy: selecting the same
+resident Game resumes it, while selecting a different Game performs destructive
+replacement and creates a fresh VM session for the new Game.
 
 The foreground/home contract defines `Game -> Home/Shell -> same Game` after a
 Game is already running. It does not change direct `--run`, debugger direct
@@ -108,6 +110,10 @@ are host/system controls, not guest cartridge boot APIs.
 
 Direct boot creates the initial VM session for the selected cartridge. It does
 not create a reusable global VM shared by later Game or Shell cartridges.
+Direct boot and debug boot MUST NOT be treated as failed-switch recovery paths:
+load or initialization failures for direct boot may transition to the crash
+flow, while Home-driven switch failures return to Home and do not restore the
+previous Game.
 
 ## 5 Firmware State Relationship
 
@@ -152,6 +158,10 @@ Direct single-cartridge boot remains a separate validation path:
 cargo run --release -p prometeu-host-desktop-winit -- --run test-cartridges/stress-console
 ```
 
+Game switch validation should cover the Home-driven two-cartridge path, for
+example `Stress Console -> Home -> Dummy Boy`, and assert that the first Game is
+not resumable after replacement.
+
 ## 8 Relationship to Other Specs
 
 - [`12-firmware-pos-and-prometeuhub.md`](12-firmware-pos-and-prometeuhub.md) defines the firmware state machine that consumes boot targets.

test-cartridges/dummy-boy/README.md

@@ -0,0 +1,11 @@
+# Dummy Boy
+
+Regenerate this cartridge with:
+
+```sh
+cargo run -p pbxgen-dummy-boy
+```
+
+Dummy Boy is a minimal visual Game cartridge used by runtime switch tests. It
+clears the frame and draws a centered square whose fill color cycles
+deterministically across frames.

test-cartridges/dummy-boy/manifest.json

@@ -0,0 +1,9 @@
+{
+  "magic": "PMTU",
+  "cartridge_version": 1,
+  "app_id": 2,
+  "title": "Dummy Boy",
+  "app_version": "0.1.0",
+  "app_mode": "Game",
+  "capabilities": ["gfx2d"]
+}