I had a flash drive that my Wii wasn't able to read. The only way I made it work was, via Parted Magic, by nuking the partition table and then creating a new one.


Do you have D2X-ALT vWii installed to Slot249?
if you use the non ALT one, the drive can only be in bottom port (USB0) and needs to be plugged in before loading any homebrew that accesses the drive.
also, use NTFS rather then WBFS.
use D2X-ALT for vWii (install base58 to Slot249)
use the new WiiFlow loader that works on vWii
set WiiFlow to read from USB when asked what device your games are on.
It could also be that the drive is not getting enough power to run right.
try using a "Y" cable to power it then use both back ports for the "Y" cable.