REQUEST] Tricking vWii into using Wii U's GameCube USB adapter natively | GBAtemp.net - The Independent Video Game Community
Tutorial: How to use your GameCube Controller Adapter for Wii U on the vWii - YouTube
Switch Gamecube Controller Adapter, Super Smash Bros Gamecube Adapter for Nintendo Switch, Wii U and PC USB with 4 Ports - Plug & Play, No Drivers Needed Nintendo Wii U Systems - Newegg.com
Play Smash Bros. on your Wii U with a GC Controller! MayFlash Adapter Overview - YouTube