NAOMI GDROM Compatibility Question

On compatibility:

I have a Japanese Guilty Gear Accent Core GDROM disk. It wont work in an American Naomi I or II System.

Does anyone know if it will it work on NAOMI I boards or do I need a NAOMI 2 board? Do I need a Japanese Naomi Board only? I keep getting ERROR 02 when I put it up in a NAOMI 1 or 2 GDROM System, but both are US boards

Not a NAOMI owner or expert, but isn’t there a replacement BIOS chip you can swap out? I seem to remember a number of NAOMI games requiring a .jp BIOS.

Looks like Southtown carries them:

Awesome, I figured it was something stupid like this, thanks toodles. I just ordered!

You’d need a japanese BIOS or a dual BIOS with revision D or higher. if you check the naomi boards there is someone that can burn you a new rom for $20.

any earlier than that, it wont even recognize your DIMM board…

^^ thats all assuming youre using Naomi1. Naomi2 should work as long as its just a japanese bios.

Guilty Gear will work in both Naomi1/2 you dont really need naomi2 for that many games except for VF.

ERROR 02 is very vague, and you’re going to run across it a lot for different reasons.

So do the alone BIOS determine the region of the game?

When I boot up my CVS 2 it says that it is a European version. So if I JUST CHANGE THE BIOS TO AMERICAN and leave the same game in will my CVS 2 game boot up to an American version? Or do I have to change the whole game and/or the motherboard to make my CVS2 an American version.

Thank you.

Yes. Not all games will work across all regions though, SFZ3U for example will only play with a Japanese BIOS.

Where can you get American Naomi Bios? What region will the game play if I buy an all region bios?


I’m sure there are many others out there, binaries can easily be downloaded anywhere you’d get files for MAME and then you just need someone with an EPROM writer that can handle M27C160 chips.

There is no such thing, though I’ve seen someone working on a homebrew/hacked BIOS that’d let you manually select the region on bootup it doesn’t appear to be released yet.

I have a somewhat similar question. Do any Japanese NAOMI games have an English option to them? The Guilty Gear games in particular since I don’t think they got a US release.

All Guilty Gear games for NAOMI are Japan-only with no English option. Slash and Accent core both require a newer Japanese Naomi BIOS as well. is a better site for information regarding NAOMI hardware.