Nestopia UE holds up pretty well, but the UI can be a bit clunky at times so do keep that in mind. That being said, these test results might be a bit misleading and that doesn’t mean that it’s not a high accuracy emulator after all. I hope you can use this information to solve your problem. Nestopia UE is ranked a bit lower on the scale of accuracy tests for NES/FDS emulators.

You also have to know that, if you use a libretro-core, the runcommand script will also check for game specific configs in the rom directory (where the game is).

You can see it should load /opt/retropie/configs/famicom/retroarch.cfg This is the command the famicom system uses as when starting a game. Your emulators.cfg in /opt/retropie/configs/famicom has to contain this : lr-nestopia = '/opt/retropie/emulators/retroarch/bin/retroarch -L /opt/retropie/libretrocores/lr-nestopia/nestopia_libretro.so -config /opt/retropie/configs/famicom/retroarch.cfg %ROM%' If you then check your dev/shm/runcommand.log it will contain more information that you can use to debug. Checking the postings, using '-retroarch -fceumm' or '-retroarch -core. Using the Use Nestopia module, it fixes those games, but other games started acting the same way. As I been using various games using FCEUmm, I noticed that some games either do not work properly or will not load at all. Look at the left hand side of LB, in the side bar, and check your system name. Make sure the associate platform name is set for both NES and FDS, and make sure the names in there match the name of your platforms in side of LaunchBox. In this menu you can also enable verbose mode ! Using FCEUmm or Nestopia on a Per Game Basis. So like the others have said make sure the core is downloaded, the command line is set properly. You have to check this by pressing a key if you run the game.

If it works for one system, it should work for more, unless some games still use game specific configs.

Nestopia core fds