Before we start, you will need a modified Wii U. Want to modify your Wii U? Here’s a tutorial.
Whether you want to make a Wii U cheat code for a game, or a trainer you need to use TCTGecko. This is a debug program and it has a Java, Python and C# variation. Whichever works best for you, those links will give you the compiled versions and are ready to use.
If you use Loadiine GX2 v0.3 and are on Wii U v5.5.1 (spoof or real) you are ready to use this program. You don’t need PyGecko as it is built in to this current Loadiine version (github nightly build).
Using your PC, edit your loadiine_gx2.cfg file on your SD card with Notepad and change LaunchPyGecko line to =1 to turn it on!
Now launch your game you want to find cheat codes for and use your preferred version of TCTGecko. The interface is similar to WiiRD.