Valid PS2 BIOS files are typically around 4MB in size and should be in the .bin format for the emulator to recognize them correctly. Usage & Troubleshooting

: Ensure the file is unzipped. If it's in a .zip or .7z archive, the emulator may not read it directly.

If a BIOS file deviates heavily from this 4MB metric, it usually indicates a corrupted dump, a bad rip, or a file filled with unnecessary dummy data, which will cause the emulator to throw a "Missing BIOS" or "Too Large" error.

Authentic PS2 BIOS dumps are typically around 4MB (specifically as a single .bin file).

To stay within legal boundaries, you should dump the BIOS from your own physical PlayStation 2 console.