Homebrew Wiiflow and USB Loader Gx freeze when loading games

[Kagetane1]

I have recently hacked my Wii and installed Wiiflow on it. Then I plugged in a fat 32 USB stick in the bottom port with super mario galaxy 2 on it. When starting the game the loading bar on the bottom finishes loading it goes into a green screen (different games its a black screen) and the wii doesn't respond anymore and is stuck there until I hard reset. To see if it was the game files itself I installed dolphin on my pc and the game ran perfectly fine there. Same happened with USB Loader Gx. Does anyone have an idea what it could be?