So, I had a similar issue. I was already on 4.3U, and I was using the mastermod version which didn't work to begin with. When I switched to the normal version, I seemingly lost all my stuff. However, I simply went into the options and changed which usb port to use from 0 to 1, and presto. Everything came back. Check if this helps. Although, Wii games still don't work... Which is why I switched to begin with.