Hello, I've been having the same issue this morning! I just deleted my update file. The thing is, I'm about to install the same update file. I don't see the DLC update (EUR) anywhere on the internet, and that is definitely what my Wii U is trying to update. Anyway, I'll see if reinstalling v33 is the key, but I'm unsure....
Edit: 25 minutes later and after re-installing the update, I check out my wifi settings. Yep.. my brother created a new connection without DNS block (he didn't know). Anyway, if you run into this issue, data management > zelda > delete update file only > reinstall update. Make sure DNS settings are all set still (look for red X on data management). Any questions, feel free to quote me and ask.