Maschell
New Super Mario Bros. U interprets HID-to-VPAD Lite Pro Controller as a Wii Remote.
If I try to play New Super Mario Bros. U with a USB controller mapped as Pro Controller 1 using HID to VPAD Lite under WUPS, the game seems to interpret it as a Wii Remote being paired rather than a Pro Controller, e.g. the title screen says to press "2" to start. The inputs are completely nonfunctional for this reason. It is possible to play if I map the controller as a GamePad instead. Other games don't display the same issue, e.g. Mario Kart 8 with a USB controller as Pro Controller 1 is completely fine.
Will edit with info on how the full HID to VPAD homebrew handles the same scenario after I've had time to test.
EDIT: The standard HID to VPAD homebrew (i.e. non-plugin version) does not display this issue.
The console sees the Wii U Pro Controller as an extension attached to a dummy Wii Remote, so Maschell might have forgotten about adding that little detail.
