I'm a little puzzled about this... correct me if I'm wrong: DS and DSLite had GBA hardware built-in to run GBA games. DSi removed the GBA cart slot but I can't find info on whether the GBA hardware from the DS was removed also. I thought not and was looking for ways to run GBA roms natively on DSi (not emulation) but found none, so I'm assuming it can't be done for whatever reason. But what's puzzling me more is why does the 3DS have a GBA mode (AGB_FIRM)? I read somewhere that GBA games in AGB_FIRM mode on 3DS run with 100% accuracy as if they're on GBA hardware (I guess minus the dark tint and blur, which can be removed on CFW). So why would Nintendo go through the trouble of making the 3DS run GBA games but not the DSi, when the latter is much closer to the DS (and by extension GBA) than the 3DS?