To play Game Boy Advance games on iOS, GBA4iOS is the best emulator you need to have.
System(s): Game Boy, Game Boy Advance, Game Boy Color
OS Supported: iOS
KiGB is the first emulator of the Game Boy series which support many different platforms like Windows – Linux – MS-DOS and even Mac.
mGBA was born in April 2013. From that day to now, games can be run smoothly without having problems.