https://gbatemp.net/threads/haxchi-v2-0-a-persistent-wiiu-hack.451071/
It requires a DS VC game (the list is on the github but you can use Brain Age, Mario Kart, NSMB, etc.) to be purchased and installed to your system memory. Then, you put the necessary install files onto your SD card, run the internet browser to get homebrew loader launched, then just follow the directions to install haxchi, which then replaces the DS game with the hombrew loader right there on the system menu. Pretty easy, and a no brainer as long as you are alright purchasing a DS game for the more convenient hombrew access.