implements PR-025

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

@@ -91,6 +91,8 @@ Current high-level flow:
 
 If VM initialization fails, firmware transitions to the crash path.
 
+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`.
+
 ## 7 Firmware States
 
 The current firmware state model includes:

docs/runtime/specs/13-cartridge.md

@@ -28,8 +28,7 @@ The runtime currently expects the following manifest fields:
   "app_id": 1234,
   "title": "My Game",
   "app_version": "1.0.0",
-  "app_mode": "Game",
+  "app_mode": "Game"
-  "entrypoint": "main"
 }
 ```
 
@@ -47,7 +46,6 @@ Current required manifest fields:
 - `title`
 - `app_version`
 - `app_mode`
-- `entrypoint`
 
 Current required file payloads:
 
@@ -70,14 +68,22 @@ The current loader validates:
 
 If validation fails, cartridge loading is rejected before execution.
 
-## 5 App Mode and Entrypoint
+## 5 App Mode and Boot Protocol
 
 `app_mode` controls firmware launch behavior:
 
 - `Game`
 - `System`
 
-`entrypoint` is passed to the VM initialization flow and may be resolved as a symbol or function identifier according to the VM/runtime contract.
+Cartridge boot is protocol-driven, not manifest-driven.
+
+The executable entrypoint of a valid cartridge is always `func_id = 0`.
+
+This means:
+
+- `manifest.json` does not select the callable to execute;
+- firmware/runtime loads the cartridge and starts execution from `func_id = 0`;
+- nominal exports may exist for linking or introspection, but they do not hold boot authority.
 
 ## 6 Assets and Preload
 

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

@@ -33,7 +33,8 @@ When the boot target is `Cartridge`:
 
 1. firmware loads the requested cartridge;
 2. cartridge metadata is read;
-3. launch behavior follows cartridge `app_mode`.
+3. launch behavior follows cartridge `app_mode`;
+4. bytecode execution starts through the cartridge boot protocol defined by the cartridge contract, not by textual entry metadata.
 
 ## 3 Launch Resolution by App Mode