Many CD-audio tracking issues present in early PSX-on-PSP software are completely resolved using the 6.60 files.

If you're still hunting for specific SCPH-XXXX BIOS files for different regions, stop. PSXONPSP660.bin is a region-free, Sony-optimized BIOS originally created for the PSP's internal PS1 emulator. It offers better compatibility and smoother performance than traditional hardware rips. Quick Stats: File Name: PSXONPSP660.bin (case-sensitive) File Size: 512 KB MD5 Hash: C53CA5908936D412331790F4426C6C33 Installation Guide: gingerbeardman/PSX - GitHub

🚨 : A real BIOS file is extremely small (usually exactly 512 KB ). If a site tries to make you download an .exe , .msi , or a massive .zip file, do not open it . It is likely malware. ⚙️ How to Use the File in Emulators