There appears to be a way to download the big update in the background which lets you continue to use the Wii U.
When it asks if you want to download the update, simply hit X to cancel. It downloads in the background anyway while you get to keep using the Wii U.
http://www.reddit.com/r/wiiu/comments/13gadt/wii_u_will_download_the_update_in_the_background/
The rEVOLution is not being televised







