I have a GA-486US (very interesting board with proprietary 32-bit bus) with a corrupted bios chip. I tried dumping the BIOS but I get nearly all FFs. I swapped the BIOS out for another board's with a different chipset and I got the board to POST but it doesn't properly configure the cache or see any memory above 640K, which is completely expected.

I cannot seem to find a copy of this BIOS anywhere online or even one with the same chipset (UM82C48). I have a MiniPRO and a compatible EEPROM so I can burn any image I want.

Any advice on where to look or what to do here? Picture of the board attached.