do not compare the wii to the wii U. the wii u is sorely lacking in power for the USB portsthis flash drive worked on a wii classic
your syscheck report is correct.
Strongly Recommend ==> use a FAT32 external hard drive and everything will be fine.
read the messages on the forum, people who use a USB key, they very often have black screens or never start, so they end up with an external hard drive with a Y-block and all that ends well (the price of an external hard drive is not very expensive, after all depends on the capacity and what you put in it as games