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

Prototype GBA BIOS

The Emulation64 Network - NextGen and Retro Emulation News and Support

Game Boy Advance / Useful Notes - TV Tropes

Proto:Game Boy Advance BIOS - The Cutting Room Floor

K1 GBA SP - The Independent Video Game Community

Gigaleak: Game Boy Advance BIOS and Game Boy Color Boot ROM

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

Altered GBA BIOS ? - The Independent Video Game

Prototype GBA BIOS

Game Boy Advance / Useful Notes - TV Tropes

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

Nintendo Game Boy Advance SMD Cap Kit - GBA

Nintendo Game Boy Advance SP - SMD Large Inductor Coils L2 / L4