WiiU: Just redownload them from CDN so you get a legit title (if you really wanted to do it offline, just download the content/code/meta folders via ftpiiu-everywhere, but the result won't be legit, beware)
Wii or Vwii: use BlueDump Mod and say no to both fakesigning TMD/ticket options to get a legit WAD... or again, just download from CDN