I did not grasp how much information is in that 500MB tech reference doc for the 8300. Wow!
probably the best documented Model T. It is clear that the ROM is 128KB, and I think it is also clear that without some custom solution, one can't make a replacement main rom for the 8300 easily. At best you might be able to program a 27C1001, and then do a custom adapter board. A normal eeprom needs both a chip select and an output enable, so some extra logic might be needed too.
