* libnds's swiSwitchToGBAMode ASM function was broken. They used r0
instead of r2 so it didn't work. It must have been correct when GBA
Exploader was last compiled more then a decade ago, but now it's broken
so this ASM function had to be reimplemented. GBA Mode switch now
appears to function as intended.
* As I currently lack a compatible slot-2 flashcart (SuperCard Lite
doesn't work even after trying a few hardcoded card types in main.c)
further testing can't be done on the rest of the code. It appears to
work but I won't know for sure until someone with compatible hardware
tests it.
