or any other special feature GBA cartridges for that matter?
Do you mean, “can homebrew use the guitar grip as input?” or “Can you use a guitar grip with a pirated version of GT that runs via R4?”
I know that games using the R4 can use the Rumble GBA cart, for sure.
I am offended by the presence of the “guitar” tag on this question. /grumblegrumble
@tonedef, hahahah took the words outta my mouth
for r4 card, you can purchase it here http://r4-3.com/