Wii u stuck update
My Wii U was stuck on the “Downloading data for update…” screen. Right now Nintendo’s servers are getting hit pretty hard and updates will be slow.
I’ve waited about an hour so far and it is only about %50 complete
What does the Wii U Update do?
Without the firmware update, Wii U systems have been unable to go online, connect to Nintendo’s Miiverse, or even play Wii games and transfer data from Wii games. That functionality should be included in this update. Source
How big is the update?
I’ve read rumors it is between 2GB and 5GB large