Recently, there was a fan translation for a ds game, NGE: Ayanami Raising Project. The game works fine on a emulator, but it will not work on a R4 cart. There was the same problem with another NGE game that came around the same time on PSP, the game will hardlock if it detects alien software. In other words, it will not work without being run as a ROM or a normal cart for un-edited DS. I am sure this could be a easy fix for anyone who knows anything about DS AP or romhacking, I sadly, do not. Me and others would love to play this on their DS, like it was meant to, so if anybody would have some extra time, maybe they could look into it. I wouldn't even know where to start.
Hey, what kind of R4 are you using? And what software? If you're using an old original R4, try using Wood R4 1.62. Hope this helps!