Does it work with Everdrive MD? Or do I have to switch controllers every time I want to play a new Master System game using a Master System controller? I've searched around and can't find anything on the subject.
I believe the SMS 1 and 2 buttons correspond to B and C on a Genesis controller, and if I recall correctly, you need A to start games. So yeah, you might be screwed trying to start a game with a Master System controller (though I don't have any firsthand experience with this).
Seems like you're right A/Start to select things, B to go back a level. Why not use C instead of A/Start? That's a pretty major oversight. So unnecessary.