If you have the perfect bundle, it comes with the GBA expansion. So you can choose GBA natively from the GBA game menu from the M3DS Real.
Also the EWIN GBA expansion works natively with the M3DS REAL.
The perfect bundles GBA expansion only fits into the DS lite though!
I bought the perfect bundle and was very upset when I figured out that the expansion didn't fit my DS phat.
Does anyone know where I can get an GBA epansion pack that fits in the DS phat?
Thank you!