Is this possible?
Yes. Just put a 32KB SRAM in a SNROM board, then compare the data lines, fix any changed ones if necessary. Wire the 2 extra to the MMC1's specified CHR address lines (Should be the 3rd and 2nd highest A, although I don't know the order) and then just wire in your ROM. If it's a 512KB ROM, tie the highest MMC1 address line to the extra PRG-ROM. That should be about it, unless it's not just a SNROM with 32KB WRAM. 
ETA: Why does the board have a hex inverter on it on bootgods databse? Is it just to make sure on power down the 32KB SRAM doesn't get corrupted? Makes the /CE coming out of the MMC1 and makes it into just CE technically to stop power down corruption I'm guessing?
ETA: Why does the board have a hex inverter on it on bootgods databse? Is it just to make sure on power down the 32KB SRAM doesn't get corrupted? Makes the /CE coming out of the MMC1 and makes it into just CE technically to stop power down corruption I'm guessing?
3gengames wrote:
ETA: Why does the board have a hex inverter on it on bootgods databse? Is it just to make sure on power down the 32KB SRAM doesn't get corrupted? Makes the /CE coming out of the MMC1 and makes it into just CE technically to stop power down corruption I'm guessing?
The MMC1 was originally designed to use the 6264's +CE enable, which a 62256 doesn't have. The inverter just flips the sense of that line.