So this is from an old post and it is still relevant because I have the same problem In Need of Help Eagerly Video Wii Usb Loader Gx Blackscreen Fix When Loading Game Youtube You can tell the loader to use that slot for better compatibility loader gx > settings > loader's settings > game's ios and loader's ios 250 usbloadergx and wiiflow are both good usb loaders users pick the one they like based on the interface's look Usb loader gx black screen on game launch i'm trying to use a new usb This works fine in USB Loader GX, even with the partition hidden from the WiiU But if I power up my WiiU with the WiiU formatted drive attached in Port 1, Nintendont no longer works (If I launch it standalone it can't find any USB FAT32 drives, if I launch it from USB Loader GX it just freezes the WiiU with a black screen
Usb Loader Gx User Manual