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,
-        discover_games_root,
+        CrashReport, ForegroundOwner, GameLifecycleEventKind, HUB_SUSPENDED_GAME_KILL_CONTROL,
+        ResidentGameState, discover_games_root,
     };
     use std::fs;
     use std::path::PathBuf;
@@ -289,20 +292,45 @@ mod tests {
         }
 
         fn add_game(&self, name: &str, with_program: bool) -> PathBuf {
+            self.add_game_with_identity(name, 42, "Stress", "1.0.0", with_program)
+        }
+
+        fn add_game_with_identity(
+            &self,
+            name: &str,
+            app_id: u32,
+            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");
-            let manifest = r#"{
+            let manifest = format!(
+                r#"{{
                     "magic": "PMTU",
                     "cartridge_version": 1,
-                "app_id": 42,
-                "title": "Stress",
-                "app_version": "1.0.0",
+                    "app_id": {app_id},
+                    "title": "{title}",
+                    "app_version": "{app_version}",
                     "app_mode": "Game"
-            }"#;
+                }}"#
+            );
             fs::write(cart.join("manifest.json"), manifest)
                 .expect("test manifest should be written");
-            if with_program {
-                fs::write(cart.join("program.pbx"), halting_program())
+            if let Some(program) = program {
+                fs::write(cart.join("program.pbx"), program)
                     .expect("test program should be written");
             }
             cart
@@ -333,6 +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,
@@ -447,6 +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);
@@ -728,6 +766,499 @@ mod tests {
         );
     }
 
+    #[test]
+    fn hub_home_clicking_different_game_terminates_previous_resident_session() {
+        let root = TestGameRoot::new();
+        root.add_game("stress", true);
+        root.add_game_with_identity("zzz-dummy", 43, "Zzz Dummy", "1.0.0", true);
+
+        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);
+        assert_eq!(firmware.os.lifecycle().resident_game_task(), Some(first_game_task));
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+        let dummy_click =
+            InputSignals { f_signal: true, x_pos: 72, y_pos: 118, ..Default::default() };
+        firmware.tick(&dummy_click, &mut platform);
+
+        assert_eq!(firmware.os.lifecycle().task_state(first_game_task), Some(TaskState::Closed));
+        assert_eq!(
+            firmware.os.lifecycle().process_state_for_task(first_game_task),
+            Ok(ProcessState::Stopped)
+        );
+        assert_eq!(
+            firmware
+                .os
+                .sessions()
+                .vm_session_for_task(first_game_task)
+                .map(|session| session.task_id),
+            None
+        );
+
+        let second_game_task = firmware
+            .os
+            .lifecycle()
+            .resident_game_task()
+            .expect("replacement game should be resident");
+        assert_ne!(second_game_task, first_game_task);
+        assert_eq!(
+            firmware
+                .os
+                .sessions()
+                .vm_session_for_task(second_game_task)
+                .map(|session| session.app_id),
+            Some(43)
+        );
+
+        firmware.tick(&InputSignals::default(), &mut platform);
+
+        match &firmware.state {
+            FirmwareState::GameRunning(step) => assert_eq!(step.task_id, second_game_task),
+            other => panic!("expected replacement GameRunning state, got {:?}", other),
+        }
+    }
+
+    #[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();
@@ -910,6 +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();
 
@@ -941,7 +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),
@@ -970,6 +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(_)));
@@ -982,7 +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};
@@ -52,7 +53,8 @@ impl HubHomeStep {
                 ctx.os.windows().set_focus(id);
                 return Some(FirmwareState::ShellRunning(ShellRunningStep::new(task_id)));
             }
-            Some(SystemProfileAction::LaunchGame { path }) => match CartridgeLoader::load(&path) {
+            Some(SystemProfileAction::LaunchGame { target }) => {
+                match CartridgeLoader::load(&target.path) {
                     Ok(cartridge) => {
                         if cartridge.app_mode == AppMode::Game
                             && let Some(resident_task_id) = ctx.os.lifecycle().resident_game_task()
@@ -68,29 +70,54 @@ impl HubHomeStep {
                                 return Some(FirmwareState::ResumeResidentGame);
                             }
 
+                            if let Err(error) = resident_game_termination::terminate_resident_game(
+                                ctx.os,
+                                ctx.platform,
+                                false,
+                            ) {
                                 ctx.os.log(
-                            LogLevel::Warn,
+                                    LogLevel::Error,
                                     LogSource::Hub,
                                     0,
                                     format!(
-                                "Cannot launch Home game {} while resident game app_id {} is active",
-                                cartridge.title, resident_app_id
+                                        "Failed to terminate resident game app_id {} before launching {}: {:?}",
+                                        resident_app_id, cartridge.title, error
                                     ),
                                 );
                                 return None;
                             }
+                        }
 
-                    return Some(FirmwareState::LoadCartridge(LoadCartridgeStep::new(cartridge)));
+                        return Some(FirmwareState::LoadCartridge(
+                            LoadCartridgeStep::new_game_switch(cartridge),
+                        ));
                     }
                     Err(error) => {
                         ctx.os.log(
                             LogLevel::Error,
                             LogSource::Hub,
                             0,
-                        format!("Failed to launch Home game {}: {:?}", path.display(), error),
+                            format!(
+                                "Failed to launch Home game {}: {:?}",
+                                target.path.display(),
+                                error
+                            ),
                         );
                     }
-            },
+                }
+            }
+            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,
@@ -20,7 +23,7 @@ pub use services::foreground::{
 };
 pub use services::fs;
 pub use services::game_library::{
-    GameLibrary, GameLibraryDiagnostic, GameLibraryEntry, discover_games_root,
+    GameLibrary, GameLibraryDiagnostic, GameLibraryEntry, GameSwitchTarget, discover_games_root,
 };
 pub use services::memcard::MemcardAsyncLaneOperation;
 pub use services::process;

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

@@ -222,6 +222,28 @@ impl<'a> LifecycleFacade<'a> {
         Ok(())
     }
 
+    pub fn terminate_resident_game(&mut self) -> Result<Option<TaskId>, LifecycleError> {
+        let Some(task_id) = self.os.foreground_stack.resident_game_task() else {
+            return Ok(None);
+        };
+
+        let process_id = process_id_for_task(self.os, task_id)?;
+
+        self.os.task_manager.close_task(task_id);
+        self.os.process_manager.mark_stopped(process_id);
+        self.os.foreground_stack.clear_resident_game(task_id);
+        self.os.vm_sessions.remove_for_task(task_id);
+        self.os.game_lifecycle_events.retain(|event| event.task_id != task_id);
+
+        if matches!(self.os.foreground_stack.owner(), ForegroundOwner::Game(owner) if owner == task_id)
+        {
+            self.os.foreground_stack.return_to_hub();
+            self.os.task_manager.clear_foreground();
+        }
+
+        Ok(Some(task_id))
+    }
+
     pub fn crash_task(
         &mut self,
         task_id: TaskId,

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/os/system_os.rs

@@ -218,6 +218,42 @@ mod tests {
         );
     }
 
+    #[test]
+    fn terminate_resident_game_closes_task_and_removes_vm_session() {
+        let mut os = SystemOS::new(None);
+        let game = os.sessions().create_vm_game_task(42, "Sector Crawl");
+
+        os.lifecycle().request_home_from_game(game).expect("home request should succeed");
+        assert_eq!(os.lifecycle().pending_game_lifecycle_events().len(), 1);
+
+        assert_eq!(os.lifecycle().terminate_resident_game(), Ok(Some(game)));
+
+        assert_eq!(os.lifecycle().resident_game(), None);
+        assert_eq!(os.lifecycle().foreground_owner(), ForegroundOwner::Hub);
+        assert_eq!(os.lifecycle().task_state(game), Some(TaskState::Closed));
+        assert_eq!(process_state_for_task(&os, game), ProcessState::Stopped);
+        assert_eq!(os.sessions().vm_session_for_task(game).map(|session| session.task_id), None);
+        assert!(os.lifecycle().pending_game_lifecycle_events().is_empty());
+    }
+
+    #[test]
+    fn terminate_resident_game_preserves_foreground_shell() {
+        let mut os = SystemOS::new(None);
+        let game = os.sessions().create_vm_game_task(42, "Sector Crawl");
+        os.lifecycle().request_home_from_game(game).expect("home request should succeed");
+        os.lifecycle().advance_game_pause_budget(game).expect("budget should expire");
+        let shell = os.sessions().create_vm_shell_task(7, "Settings");
+
+        assert_eq!(os.lifecycle().terminate_resident_game(), Ok(Some(game)));
+
+        assert_eq!(os.lifecycle().foreground_owner(), ForegroundOwner::Shell(shell));
+        assert_eq!(os.lifecycle().resident_game(), None);
+        assert_eq!(os.lifecycle().task_state(game), Some(TaskState::Closed));
+        assert_eq!(process_state_for_task(&os, game), ProcessState::Stopped);
+        assert_eq!(os.sessions().vm_session_for_task(game).map(|session| session.task_id), None);
+        assert_eq!(os.lifecycle().task_state(shell), Some(TaskState::Foreground));
+    }
+
     #[test]
     fn vm_game_task_creates_vm_session() {
         let mut os = SystemOS::new(None);

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

@@ -1,12 +1,12 @@
 use crate::task::TaskId;
-use crate::{CrashReport, GameLibrary, SystemOS};
+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::{
     FrameId, GfxUiCommand, InputPlatform, InputSignals, RenderSubmission, RuntimePlatform,
     ShellUiFramePacket,
 };
-use std::path::PathBuf;
 
 const SHELL_A_BUTTON: Rect = Rect { x: 112, y: 172, w: 112, h: 32 };
 const SHELL_B_BUTTON: Rect = Rect { x: 256, y: 172, w: 112, h: 32 };
@@ -20,6 +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 };
 
@@ -32,6 +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 {
@@ -83,7 +86,8 @@ impl NativeShellApp {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum SystemProfileAction {
     LaunchNativeShell(NativeShellApp),
-    LaunchGame { path: PathBuf },
+    LaunchGame { target: GameSwitchTarget },
+    KillResidentGame,
     CloseShell,
 }
 
@@ -132,12 +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);
         }
@@ -150,7 +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() {
@@ -233,6 +245,7 @@ fn action_for_click(
     y: i32,
     pressed: bool,
     game_entries: &[crate::GameLibraryEntry],
+    suspended_game: Option<&SuspendedGameIndicator>,
 ) -> Option<SystemProfileAction> {
     if !pressed {
         return None;
@@ -242,6 +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)
@@ -249,7 +266,7 @@ fn action_for_click(
         .find(|(index, _entry)| rect_contains(game_row_rect(*index), x, y))
         .map(|(_index, entry)| entry)
     {
-        return Some(SystemProfileAction::LaunchGame { path: entry.path.clone() });
+        return Some(SystemProfileAction::LaunchGame { target: entry.switch_target() });
     }
 
     HOME_BUTTONS
@@ -258,6 +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,
@@ -282,6 +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 });
@@ -321,6 +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)
 }
 
@@ -423,6 +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 });
 }
@@ -434,6 +507,7 @@ mod tests {
     use crate::windows::WindowOwner;
     use prometeu_drivers::TestPlatform;
     use prometeu_hal::{InputSignals, RuntimePlatform};
+    use std::path::PathBuf;
 
     fn focused_native_shell_fixture(
         signals: &InputSignals,
@@ -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]
@@ -535,19 +622,35 @@ mod tests {
             discovered_at: std::time::SystemTime::UNIX_EPOCH,
         };
 
+        let action = action_for_click(
+            false,
+            GAME_ROW_X,
+            GAME_ROW_Y,
+            true,
+            std::slice::from_ref(&entry),
+            None,
+        );
+
         assert_eq!(
-            action_for_click(false, GAME_ROW_X, GAME_ROW_Y, true, std::slice::from_ref(&entry)),
-            Some(SystemProfileAction::LaunchGame { path: entry.path.clone() })
+            action,
+            Some(SystemProfileAction::LaunchGame {
+                target: GameSwitchTarget {
+                    path: entry.path.clone(),
+                    app_id: 42,
+                    title: "Stress".to_string(),
+                    app_version: "1.0.0".to_string(),
+                }
+            })
         );
     }
 
     #[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]
@@ -561,7 +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| {
@@ -569,6 +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

@@ -25,6 +25,29 @@ impl GameLibraryEntry {
             discovered_at,
         }
     }
+
+    pub fn switch_target(&self) -> GameSwitchTarget {
+        GameSwitchTarget::from_entry(self)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct GameSwitchTarget {
+    pub path: PathBuf,
+    pub app_id: u32,
+    pub title: String,
+    pub app_version: String,
+}
+
+impl GameSwitchTarget {
+    pub fn from_entry(entry: &GameLibraryEntry) -> Self {
+        Self {
+            path: entry.path.clone(),
+            app_id: entry.app_id,
+            title: entry.title.clone(),
+            app_version: entry.app_version.clone(),
+        }
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -256,6 +279,31 @@ mod tests {
         }));
     }
 
+    #[test]
+    fn switch_target_preserves_resolved_identity() {
+        let path = PathBuf::from("test-cartridges/stress-console");
+        let entry = GameLibraryEntry::new(
+            path.clone(),
+            CartridgeManifest {
+                magic: "PMTU".to_string(),
+                cartridge_version: 1,
+                app_id: 42,
+                title: "Stress".to_string(),
+                app_version: "1.0.0".to_string(),
+                app_mode: AppMode::Game,
+                capabilities: vec![],
+            },
+            UNIX_EPOCH,
+        );
+
+        let target = entry.switch_target();
+
+        assert_eq!(target.path, path);
+        assert_eq!(target.app_id, 42);
+        assert_eq!(target.title, "Stress");
+        assert_eq!(target.app_version, "1.0.0");
+    }
+
     #[test]
     fn missing_root_returns_diagnostic_and_no_entries() {
         let root = TestRoot::new();
@@ -267,4 +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/console/prometeu-system/src/services/vm_session.rs

@@ -121,6 +121,10 @@ impl VmSessionRegistry {
         self.get_mut(VmSessionId(task_id))
     }
 
+    pub fn remove_for_task(&mut self, task_id: TaskId) -> Option<VmSession> {
+        self.sessions.remove(&VmSessionId(task_id))
+    }
+
     pub fn resident_game(&self) -> Option<&VmSession> {
         self.sessions.values().find(|session| session.app_mode == AppMode::Game)
     }
@@ -231,6 +235,31 @@ mod tests {
         assert_eq!(registry.resident_game_for_app(43).map(|session| session.task_id), None);
     }
 
+    #[test]
+    fn remove_for_task_removes_only_matching_session() {
+        let game_process = Process::new(ProcessId(1), 42, "Stress", ProcessKind::VmGame);
+        let game_task = Task::new(TaskId(7), game_process.id, 42, "Stress", TaskKind::Game);
+        let shell_process = Process::new(ProcessId(2), 9, "Shell", ProcessKind::VmShell);
+        let shell_task = Task::new(TaskId(8), shell_process.id, 9, "Shell", TaskKind::Shell);
+        let mut registry = VmSessionRegistry::new();
+
+        registry
+            .create_for_task(&game_task, &game_process, "", None, Arc::new(AtomicU32::new(0)))
+            .expect("game session should create");
+        registry
+            .create_for_task(&shell_task, &shell_process, "", None, Arc::new(AtomicU32::new(0)))
+            .expect("shell session should create");
+
+        let removed = registry.remove_for_task(game_task.id).expect("game session should remove");
+
+        assert_eq!(removed.task_id, game_task.id);
+        assert_eq!(registry.for_task(game_task.id).map(|session| session.task_id), None);
+        assert_eq!(
+            registry.for_task(shell_task.id).map(|session| session.task_id),
+            Some(shell_task.id)
+        );
+    }
+
     #[test]
     fn session_runtime_state_is_independent_per_session() {
         let game_process = Process::new(ProcessId(1), 42, "Stress", ProcessKind::VmGame);

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,
-    last_presented_frame: Option<u64>,
+    latest_published_frame: Option<PresentationFrameMarker>,
+    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) {
-        if frame_index > self.latest_published_frame {
-            self.latest_published_frame = frame_index;
+    fn note_published_frame(&mut self, ownership: RenderOwnership, frame_id: u64) {
+        let marker = PresentationFrameMarker { ownership, frame_id };
+        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":39,"PLN":157,"LSN":53,"CLSN":1}}
-{"type":"discussion","id":"DSC-0043","status":"open","ticket":"system-os-cartridge-switch-orchestrator","title":"SystemOS Cartridge Switch Orchestrator","created_at":"2026-07-03","updated_at":"2026-07-03","tags":["runtime","os","lifecycle","game","cartridge","architecture"],"agendas":[{"id":"AGD-0044","file":"AGD-0044-systemos-cartridge-switch-orchestrator.md","status":"open","created_at":"2026-07-03","updated_at":"2026-07-03"}],"decisions":[],"plans":[],"lessons":[]}
+{"type":"meta","next_id":{"DSC":45,"AGD":48,"DEC":41,"PLN":167,"LSN":55,"CLSN":1}}
+{"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

@@ -1,145 +0,0 @@
----
-id: AGD-0044
-ticket: system-os-cartridge-switch-orchestrator
-title: SystemOS Cartridge Switch Orchestrator
-status: open
-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
-
-Recomendo a Opcao A agora, com esta agenda aberta como marcador explicito de
-escopo futuro.
-
-A ordem preferida passa a ser:
-
-1. fechar a `AGD-0041` para definir foreground, pausa/suspensao, Shell no
-   foreground e retorno ao mesmo Game;
-2. voltar para esta agenda e decidir o contrato do orquestrador de troca de
-   cartucho no SystemOS;
-3. so entao planejar a execucao de `Game A -> Home -> Game B`.
-
-Se durante a `AGD-0041` aparecer uma decisao que exige antecipar parte do
-orquestrador, esta agenda deve ser reaberta/atualizada com a dependencia
-concreta em vez de esconder a troca de cartucho dentro da agenda de foreground.
-
-## Perguntas em Aberto
-
-- [ ] Depois da `AGD-0041`, qual estado representa um Game que sera descartado
-  em vez de retomado?
-- [ ] O fechamento do Game atual e observavel para o firmware/game, ou e uma
-  destruicao interna do SystemOS?
-- [ ] Quais estados cartridge-scoped devem ser limpos antes do novo load: VM,
-  assets, FS handles, input, audio, render ownership, telemetry, logs?
-- [ ] Se o novo cartucho falha ao carregar, o sistema volta ao Home, mostra uma
-  tela de erro, ou tenta preservar o Game anterior?
-- [ ] Como a resolucao do novo alvo e representada sem depender de catalogo
-  completo ou `.pmc`?
-- [ ] Qual evidencia minima prova `Game A -> Home -> Game B` sem depender de UX
-  final de launcher?
-
-## 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.
-
-## Resolution
-
-Ainda em aberto.

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 exists is outside the v1 foreground contract and must not create a
-second resident Game session. VM-backed Shell loading creates a distinct Shell
+resident Game from Home resumes that session. Selecting a different Game from
+Home is a SystemOS-owned Game switch and MUST be destructive replacement:
+
+```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
-profile. That orchestration belongs to the foreground/home and cartridge switch
-contracts.
+Game-to-game switching after a game is already active is not a boot profile.
+That orchestration belongs to the foreground/home and cartridge switch
+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"]
+}