3 - Error Rom File Size Does Not Match Existing Bios Size Fix -

Some tools are verbose. They might say: "Expected: 262144 bytes, Got: 263168 bytes" Write down the expected number.

For Neo Geo BIOS: The neo-po.rom might be 256KB but you have a 512KB file. That 512KB file is actually two 256KB ROMs byte-interleaved. Use a deinterleaving tool: split -b 256 or a specialized ROMsplitter. 3 - error rom file size does not match existing bios size