@MrRean For Windows users (maybe also Wine, didn't test it) there is a way to get the game update files!
1.)
Pull your WiiU out off the outlet! If you don't want to risk updating the fw!
2.)
Disable the URL-blacklist.
3.) Get UWizard, goto:
Settings->Search for Updates (
to get the latest version and database)
3.1.) Close UWizard for now.
4.) Search for the Wii U common key online. Less than 1min search.
5.) Use a HexEditor of your choice, create an empty file and copy the key inside of it.
6.) Save it as "ckey.bin" in the same directory as the UWizard exe is.
[do steps 4-6 with the "Espresso ancast key", but name the file it differently]
(looks like the Ancast key is used for something else, can someone concretise?)
7.) Open UWizard again (or restart it, if you didn't close it before)
8.) Under the "Settings" tab check whether to the right of "Wii U Common Key" and "Wii U Espresso Ancast Key" in a green box stating that it accords to the "SHA1-Hash". If not, point to the files containing the keys!
(or directly enter the keys [not recommended this way due to potential loss])
9.) Go to the "NUS Downloader U" tab and choose a game in the list to the right! (or add one from
here)
10.) Tick the "Decrypt content" box and start the download.
10.1.)
Wait until everything is finished
10.2) Continue with any of the other games until you have all of the files you need.
11.) Enable your URL-blacklist again! (make sure you can't access ANY of the URLs!)
12.) Put the Wii U into the outlet again and enjoy using the updates!
UWizard does have some other interesting features. Look through the tabs and explore!
And sorry if I named some of the tabs and strings wrong. I didn't use the English version!