prometeu-runtime/docs/specs/topics/chapter-14.md

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Boot Profiles

Version: 1.0 Status: Proposal

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1. Objective

Define how Prometeu decides what to execute at startup:

• Hub
• Automatic cartridge
• Debug mode

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2. BootTarget Concept

At the beginning of boot, the POS resolves a target:

enum BootTarget {
  Hub,
  Cartridge { path: String, debug: bool },
}

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3. General Rules

If BootTarget == Hub

• Firmware enters HubHome
• No cartridge is automatically loaded

If BootTarget == Cartridge

1. Load cartridge
2. Read app_mode in the manifest
3. Apply rules:

• Game:

  • Enter RunningGame

• System:

  • Stay in HubHome
  • Open the app as a window/system tool

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4. Host CLI

Default boot

prometeu

Result: enters the Hub

Run cartridge

prometeu run <cartridge>

Result:

• Game → enters directly into the game
• System → opens as a tool in the Hub

Run with debugger

prometeu debug <cartridge>

Result:

• Same flow as run
• Runtime starts in debug mode
• Waits for connection from the Java Debugger

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5. Firmware States

Firmware maintains only:

• Boot
• HubHome
• RunningGame
• AppCrashed

System apps never change the firmware state.

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6. Behavior on Real Hardware (future)

• If miniSD/physical cartridge is present at boot:

  • POS can:

    • always go to the Hub, or
    • auto-execute according to user configuration

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7. Integration with Debugger

When debug == true:

• Runtime:

  • Initializes
  • Opens DevTools socket
  • Waits for start command

• Only after that does it start cartridge execution

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8. Stability

• BootTarget is an internal POS contract
• Host CLI must respect these rules
• New boot modes must be compatible extensions

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