I got a couple of flashcarts and DS Lites, a Supercard DSTwo (EOS 1.14, FWUpdate 1.25) and an Acekard 2i (Akaio 1.9.0). For the most part local multiplayer between these two works perfectly. Titles like NSMBDS, MKDS, Clubhouse Games, Mario Hoops, Mario Party DS (multicart debug patch), etc etc...