PM-41 NTSC J about psnee HOT 2 OPEN

Mid/Late model Japanese systems have to have the discs patched to claim to be NTSC-J or have their entire BIOS chips replaced, because there's a secondary check in the BIOS code that the modchip (which manipulates the mechacon) cannot bypass (yet, at least). The only PAL PSX that does this is the PM-41(2), and no north american units do the check.

So it's easiest to patch your game discs so that the BIOS thinks they're NTSC-J region. But it's not really something within the scope of this modchip to be able to fix (unless someone makes a hack like the one for the PAL PM-41(2) - which the ATTiny85 might not have enough pins to do anyway).

from psnee.

Thanks for the explanation. I think this is very important information and should be written down in the Readme. Up until now I thought only PAL PM-41 boards needed a BIOS patch to run region free.

from psnee.