I’ve had this issue spontaneously occur on my 3DS where DS games play with the top screen stretched out, almost the full 16:9 but not quite. Holding select to playing it in the original resolution only fucks the screen up even more. I have no idea what caused this, maybe the NDS forwarder I installed a while ago? I can’t find any help online because all the results are how to make DS games play in 16:9 which I don’t want. Any help would be greatly appreciated