Before I answer this, let me say that while not all cases require this, an overwhelming majority does. 90% of all "not working" cases can be resolved with this, 9% are fixed by removing Soft Reset and 1% won't work. I will not speak for the cards I haven't used because that is how misleading information is presented. I can speak for the cards I have used (M3 CF/SD and G6 Lite). If you are unable to play Download Play games when sending from your flashcart, your receiving DS must be flashed. The sending DS can be flashed or not, it doesn't matter. I repeat, the receiving DS must be flashed. A passcard/superkey in the DS slot will not affect download play, how could it? If you plan on asking if having a passcard3 instead of flashme will work in the receiver, the answer is no. There have been reports about EZ4/SC maybe working with specific games, but your best bet is to just flash the receiving DS.