PSXONPSP660.bin BIOS is widely considered the best performing and most compatible BIOS

How to proceed (high-level steps to use a legally obtained BIOS)

  1. Dump the BIOS from your own PS1 hardware using appropriate hardware tools and software.
  2. Transfer the BIOS file (e.g., PSXonPSP660.bin) to the emulator’s required directory on the PSP memory stick.
  3. Load the emulator/plugin and point it to the BIOS file if needed.
  4. Run legally owned PS1 game images.

Part 6: Alternatives to psxonpsp660.bin

If you are struggling with legality or technical hurdles, ask yourself: Do you really need this file?

Improved CDDA Audio: Fixes issues where background music wouldn't loop.

: It allows you to play games from any region (NTSC-U, NTSC-J, PAL) without switching BIOS files. : Like most PSX BIOS files, it is exactly

A BIOS (Basic Input/Output System) is low-level firmware that initializes hardware and provides core services—like reading input, displaying graphics, or accessing storage—before the main operating system or game takes over. Original consoles have a unique BIOS chip. When you run an emulator on your PC or smartphone, that emulator is essentially pretending to be the console hardware. However, some of the original console’s low-level instructions are proprietary and copyrighted by Sony.

To enable this mode, RetroArch’s PCSX-ReARMed core requires a POPS BIOS file—specifically named psxonpsp660.bin —placed in the system folder.

  1. Performance on low-end hardware: The PSP’s official emulator is incredibly lightweight. On a Raspberry Pi or an old Android phone, running PS1 games via the POPS system (using psxonpsp660.bin) is often faster than running a traditional PS1 emulator like Beetle PSX or DuckStation.
  2. Compatibility quirks: Some obscure PS1 games have glitches on standard emulators but run perfectly within Sony’s proprietary POPS environment.

Pro Tip: Use a checksum verifier. The correct MD5 for a clean psxonpsp660.bin is widely documented. If your file doesn’t match, it’s either corrupted or a fake.