There is no BIOS selection. For :
If you are a RetroArch fan, keep in mind that PS Vita emulation is best handled by the standalone emulator. While RetroArch is king for older systems like the SNES or PS1 (which do require specific BIOS files in the system folder), Vita-specific emulation still mostly happens through the dedicated Vita3K project. 4. Why You Need Official Files Vita3K - General Guide - RetroDECK Wiki ps vita bios best
To get the most accurate and stable experience, you should use the latest official firmware files directly from Sony. Official System Firmware There is no BIOS selection