The psxonpsp660bin file is the PlayStation BIOS extracted specifically from the PSP's official firmware version 6.60.
If you are trying to get this working in an emulator (like RetroArch) or hardware (PSIO): psxonpsp660bin archiveorg new
This is a PlayStation 1 BIOS file (Basic Input/Output System). Specifically, it is a version of the PS1 firmware (version 6.60) that was extracted from the official Sony PlayStation emulator released for the PSP (PlayStation Portable). The psxonpsp660bin file is the PlayStation BIOS extracted