Help, WUP GX2 Error: Not a game, game update, DLC, demo or version title (I'm using Haxchi, and downloaded the title from Wii U USB Helper into my SD Card using titlekeys.ovh) :
Download and Install Wii U Games with USB Helper Launcher - CFWaifu
Homebrew: Hack Nintendo WiiU and Install Games From Backup - digiMoot:
HOW TO INSTALL WUP INSTALL GX2 ON WII U MENU [5.5.5] - YouTube