The cores that request these files are: Sony - PlayStation (Beetle PSX HW), Sony - PlayStation (Beetle PSX), Sony - PlayStation (PCSX ReARMed).

scph5500.bin (PS1 JP BIOS), scph5501.bin (PS1 US BIOS) and scph5502.bin (PS1 EU BIOS) are required.

psxonpsp660.bin (PSP PS1 BIOS) and ps1_rom.bin (PS3 PS1 BIOS) are optional.