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Table of Contents
BootFriend is a custom “firmware” solution compatible with the WonderSwan Color and SwanCrystal handheld consoles. It provides a custom splash screen with the following features:
- Customize the logo through a web editor (including setting a faster boot time),
- Load .bfb programs to RAM via serial port - this is similar to the GBA's “Multiboot” functionality,
- Launch Pocket Challenge V2 cartridges on WonderSwan consoles in “pin-strap mode”.
- Use the installer to “unbrick” consoles with corrupted internal EEPROMs.
Installation
The installation process depends on what devices you own.
Loading .bfb programs
Loading .bfb programs requires a serial port adapter. Multiple solutions exist:
- The official RS-232 adapter bundled with the WonderWitch.
- ExtFriend - DIY, based on the RP2040/Raspberry Pi Pico, can be built at home for about $10-$15.
- RetroOnyx USB Link Cable - $85 as of writing, high quality.
To load a .bfb program, first initiate a 38400 bps XMODEM file transfer on the PC side, then turn on the console with BootFriend installed. Some guides are available to help:
List of available programs
- WS Backup Tool - backup/restore boot ROM, game data and save data
Troubleshooting
If done correctly, the PC should notify you that a transfer has started. During this time, the handheld's screen should populate with dots. Each dot corresponds to one block - 128 bytes - of data.
If a letter appears, that signifies an error. Some errors are recoverable and will result in an automatic attempt to retry transfer; others will cause the transfer to stop.
- A, B, K - corrupt information in transferred block,
- C - transfer cancelled by sending side,
- D - received file has invalid format,
- R - the received file's requested RAM area is out of permitted range.