Be careful current and soon to be Wii U owners. The console being shut down during initial update can brick the console.

[BuckStud]

Xxain said:

Barozi said:
Is the automatic shutdown activated by default ? If so when does it shut down 

an earlier article said it was an hour and it is default, but I think this guy literally just unplugged his Wii U during a update so it might not even apply.

The system automatically disables the auto shut off while it is installing the update.