I also wonder how to do this.
I am using a 3.5 "external HDD and It also is formatted as WiiU HDD now. But I can only transfer stuff from the WiiU to the HDD and then use it from there. I cannot tell my WiU "save to 500GB harddrive".
it always wants to download to the 32gb flash memory. Which didnt work with W101 because I just hat 9GB left or so... so i had to move everything to the harddrive and then was able to download W101....








