Retroarch says bios files are missing - RG34XX

Bios files should go in /muos/bios
On sd1 or sd2
If a /muos/bios folder is present on sd2, /run/muos/storage/bios will read from that folder, if not, it will read from sd1.

If you have a valid and named correctly gba bios on /muos/bios it will be detected without issues.

There’s a section about bios in here: