Well, I saw an old topic about the R4 playing GBA ROMs. Many people were saying 'no, it's impossible' or 'you n00b everyone knows you cant'. Someone even posted this: In actual fact, the R4 is capable of playing .GBA Files. The thing is though, no one has bothered making some firmware that can, indeed load GBA games. Or maybe something that will convert GBA ROMs to NDS ROMs (obviously using only one screen). So, it is possible. All we need is an expert to come and lift this project. If there is anyone out there who wants to take this challenge, go ahead. We'll cheer you on.