I bought my Wii U few months ago premoded, but it's Japanese model :D It was moded, but it only has few translates, it was horible, so I completely reinstall firmware to Europe including vWii. It's wonderful what homebrew can do :) My 2DS is moded too :D
you can also mod your vWii its pretty easy did it too
how did u put your vWii to english? I am in 5.5.6U
So you went from Japanese firmware to North america and your vWii is still in Japanese ? If so, yo need to use vWii Decaffeinator to completly wipe vWii partition, afterwards switch back to nintendo network and unblock updates.
Then go to settings and perform system update, it takes quite a bit of time for the update to download and install, but it will download all vWi files that we removed and it will work again and in English.
It's realy necessary to unblock updates in aroma menu, because it recreate update folder, without that update folder no update will appear. I also must disconnect USB HDD and sd card for update to appear.
This update process is realy pain, yo must figure out what to do, like me disconnect SD and HDD, try reboot console, but without this update vWii is lost, if you try open vWi, console freezes. Look for tutorial online. I wish you luck and I hope i help you little :)