Unlike modern PC games that rely on an operating system’s drivers, the original PlayStation and PSP were closed systems. The BIOS on these consoles is a small, proprietary firmware stored on a ROM chip on the motherboard. It contains the lowest-level code necessary to boot the console: startup routines, hardware initialization, and most importantly, system calls for graphics, audio, and input.

When Sony released the PSP, they wanted to sell classic PS1 games on the PlayStation Store. To do this, Sony engineers built a proprietary, highly optimized PS1 emulator directly into the PSP’s firmware. This emulator was not a separate application; it was a core system component.

(the 660 in the filename) was one of the last major, stable revisions for the PSP. The psxonpsp660.bin file is effectively a dump of that specific POPS BIOS module extracted from a legitimate PSP running firmware 6.60. Why Do PC Emulators Use This File? You might ask: I am not using a PSP; I am using a PS1 emulator on my Windows PC. Why would I need a PSP’s PS1 emulator BIOS?

Each PS1 classic downloaded from the PSN store came packaged with a specific BIOS emulation layer. As Sony updated the PSP’s firmware (from version 1.0 to 6.61), they improved the POPS emulator for better compatibility and performance.