I don't see why you couldn't do that but just to be sure, prepare another backup after the transfer and accustom yourself with ohneswanzenegger in case things go sour.

 

One question though - any reason why you'd want to do that? If you want to transfer pirated *.wad's onto the new system then it won't work - you have better chances using vWii on the WiiU itself. To me it seems a little bit pointless.

 

You can copy those onto an SD card, can you not? You don't have to transfer the entire system to do it, and for all the pesky locked save files there's homebrew to unlock them.

 

Well done. I'm glad that I've just saved you time, effort and grey hair.

 

I assume you mean back it up on the Wii side.

You can do that easily, transfer all your content, and keep your saves and purchased content installed on both machines. It's a rather common thing to do around here.

In fact I would recommend it. Why? Because, as it turns out, my Wii U did NOT transfer all my savegames from my Wii when I did the transfer like it was supposed to. It completely ignored a bunch of my saves during transfer, like SSBB (actually Savegame Manager GX would not transfer my SSBB save either for some reason, even though the game can read it fine on my Wii) and I'm pretty sure it ignored a lot of other ones too as my vWii Data Management has very few pages of content on it compared to my Wii.

So if I didn't have that NAND backup, it might've deleted all the saves on the Wii (it isn't supposed to touch content it doesn't transfer, but then again it's not supposed to ignore half my save files either, so the result would be unpredictable) and I would have to start over in a lot of games.