Choosing a Hard Disk Drive. A lot of Hard Drives are compatible with the Wii, but you might want to check the http://wiki.gbatemp. Google Code Wii Backup Loaders - Wii Hacks Guide
: One of the few flash drive lines known for decent (though not perfect) success rates. Likely Compatible (Mixed Results) usb loader gx usb compatibility list
If you must use a flash drive, these metal-cased options handle the heat of constant reading better than plastic ones. Choosing a Hard Disk Drive