As 3DS Firmware updated to 3DS to V2.02.0.0-2?J,E,U),there have some 3DS Flashcard that below V2.0 be blocked.Yet,just some not all,there is a v2.0 working list :
R4i gold 3DS
Acekard 2i
Supercard DSTwo
So,here i made a comparison of this three flashcart from their commons and difference...