I have a Japanese 3DS XL/LL that I homebrewed with the latest version of Luma. I also did a region change to US and everything seemed to work fine. I inserted a DS cartridge game and it wouldn't load. I inserted another DS cartridge game and it loaded just fine. I then tried my Pokemon Ultra Sun cartridge game but it would not load. I was able to load my Shovel Knight cartridge game just fine on it though. I thought maybe the cartridge reader was bad so I installed Pokemon Ultra Sun and had the same issue, the screens just stay black after opening the installed game. I tried a few games and some load up just fine and others don't and I don't see a pattern. Does anyone know what could be causing this? I've installed custom firmware and region changed many 3DS and have never had this issue.