It looks like you have to use an external hard drive with a separate power source. I can't understand Japanese, so I'm going by the big red exclamation point that appeared when the hard drive was connected to the Wii U without separate power, lol. Dual USB will work; single USB is not guaranteed to work.
Same with jump drives. Probably won't work.
I have no idea.
Last edited by Pineconn; 11-14-2012 at 12:16 PM.