I have tried both Super Mario Advanced and Pokemon Sapphire, both load to the same black screen on the WiiU. Advanced Wars and Pokemkn Fire Red work great with the GBS Zelda base
I have done what the forum asks and when I try to boot Retroarch from Hombrew it continues to bring me back to homebrew. i also have installed it on the homepage and it brings me back to the wii menu. Any suggestions?