You cannot use Game Genie codes pointing to ROM at all in Genesis.

[getCursorsExe]

I think this has to do with #3246. Example: NKCA-LABR normally sets address 0x05442E to 0x0062. But #3246 prevents that from working. This is due to all cheats pointing to M68K BUS memory domain, while cheats pointing to ROM should land on MD CART instead.

[ReyVGM]

What if you manually change the domain after adding the cheat, will it still work?

[getCursorsExe]

Yes it will.

[ReyVGM]

The problem is not that you can't use GG codes, the problem is that they point to the wrong domain?

[YoshiRulz]

Try this dev build.

edit: Closing as stale. My branch will remain around in the aether, if it disappears from this repo just hit me up and I'll get you a copy.