kyuusaku wrote:
MMC4 is different in that BOTH 4K CHR banks are switched via tile access.
Well I suppose that's also the case of the MMC2. I could be wrong, but the only difference is that MMC2 has 8k swappable / 24k fixed PRG bankswitching, while the MMC4 has the more standard 16k swappable / 16k fixed. Also MMC4 has SRAM+Battery support, MMC2 doesn't.
It should be very possible to hack punchout to run on a Fire Emblem Cart if you expand the PRG a bit. You'll have to copy the content of fixed bank $a000-$bfff between each 8kb PRG bank and that should work (expanding PRG from 128k to 256k).
If you made your own MMC2 game or demo but only have a MMC4 board to test, yes you could use this trick as well (other people could probably test it on a real MMC2 if you ask)