I have explained to you why powering it with a y cable is not a good idea. If you still want to do that then good luck. I really don't understand why people ask for help and suggestions when they are not going to listen. I spent time out of my day to try and find the best solution for you, and to also write up a long and thorough reason why you shouldn't use a y cable to supply power. maybe you will be lucky and not damage your usb board in your wii u. a lot of people get away with it. That said, I have repaired several that had burnt resistors due to using a Y cable and the usb hdd had tried to pull too much amps. I'm done.