# Boot Profiles

Domain: firmware boot flow
Function: normative

This chapter defines how PROMETEU chooses what to execute at startup.

## 1 Boot Target

The current firmware-side boot target concept is:

```rust
enum BootTarget {
  Hub,
  Cartridge { path: String, debug: bool, debug_port: u16 },
}
```

This is a firmware/host orchestration contract, not a guest-visible ABI.

## 2 Boot Modes

### Hub

When the boot target is `Hub`:

- firmware boots into the Hub flow;
- no cartridge is auto-launched.

### Cartridge

When the boot target is `Cartridge`:

1. firmware loads the requested cartridge;
2. cartridge metadata is read;
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

For a cartridge boot target:

- `Game` cartridges transition into game-running flow;
- `System` cartridges are initialized and integrated into the Hub/window path.

This preserves the distinction between machine firmware state and app execution mode.

## 4 Host CLI Relationship

Typical host-facing boot intents are:

- default start -> enter Hub;
- run cartridge -> boot with cartridge target;
- debug cartridge -> boot with cartridge target plus debug mode parameters.

The CLI is an entry surface for boot target selection; the firmware contract remains the same underneath.

## 5 Firmware State Relationship

Boot target selection feeds into firmware states such as:

- `Reset`
- `SplashScreen`
- `LaunchHub`
- `HubHome`
- `LoadCartridge`
- `GameRunning`
- `AppCrashes`

Boot target is not itself a firmware state. It is an input to the firmware state machine.

## 6 Debug Boot

When booting a cartridge in debug mode:

- firmware/runtime uses the cartridge target path;
- debugger-related startup behavior is enabled;
- execution still follows the same cartridge/app-mode resolution path.

Debug mode changes orchestration, not the cartridge contract.

## 7 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.
- [`13-cartridge.md`](13-cartridge.md) defines cartridge structure.
- [`10-debug-inspection-and-profiling.md`](10-debug-inspection-and-profiling.md) defines the observability/debugging layer.