Prototype GBA BIOS

No clue where I picked this up, but it's definitely strange. In addition to the changed sound, using this BIOS causes minor graphics corruption in some game

K1 GBA SP - The Independent Video Game Community

Prototypes by system/Game Boy Advance - Hidden Palace

New Prototype DS Lite Discovered - The Independent

Lost GBA Early Prototype Firmware/BIOS Found!!!

Nintendo Lot Check ROM Leak - Retro Reversing (Reverse Engineering)

Nintendo GameCube Prototype From Space World 2000 Expo is

Air Race (prototype) ROM < MAME ROMs

Game Boy Advance / Useful Notes - TV Tropes

Proto:Game Boy Advance BIOS - The Cutting Room Floor

Prototype Mega EverDrive Pro Update

This Game Boy Advance DX - i think I may have bought a rare