Hi, a friend of mine recently bought an used Wii U but there's a big problem with it, you see, when he boots up the console it asks him to log in with one of the Nintendo Network accounts linked to the console instead of just taking him to the main menu, normally you could just link your own account and then format the thing, but for whatever reason the previous owner (a kid, if that's any useful) had used all twelve accounts slots the console has, and he does not know any of the passwords to those accounts, so my ultimately my friend can't access system settings and format it which is a pain in the arse, if anybody knows how to fix this or if theres any secret recovery mode or something that'd be amazing. Thank you a bunch.