Psxonpsp660.bin -

: Some custom firmware tools use this file as a reference.

: Similar to other firmware files, it is generally considered illegal to download these files from the internet; users are encouraged to extract them from their own PSP hardware. psxonpsp660.bin

If you need PS1 emulation on a PSP emulator: : Some custom firmware tools use this file as a reference

Emulators require a BIOS file to function correctly, as they mimic the startup sequence of the original console hardware. psxonpsp660.bin