BootFriend is a custom splash screen-based boot process patch designed for the WonderSwan Color and SwanCrystal handheld consoles.
The .bfb format is used to create binaries that can be booted by BootFriend.
- bytes 0-1 - magic (0x62 0x46, or 'bF').
- bytes 2-3 - starting address, little-endian.
- If the address is 0xFFFF, the code is assumed to be position-independent.
- BootFriend currently only supports loading code between 0x6800 and 0xFDFF.
- bytes 4... - program data.
The entrypoint is as follows:
- 0???:0000 - position-independent code (starting address 0xFFFF),
- 0000:ABCD - any other starting address (f.e. 0xABCD).