How do I patch or add .GCT code into Wii ISOs

[IgelWH]

I wanna patch my MKW ISO into a custom track distribution, but there is one thing i need to do, i need to add a GCT code and I don't know how to do that. Anyone ideas?

[Leseratte10]

You can use Wiimms tools (wstrt) to include a GCT in a Mario Kart Wii ISO: https://szs.wiimm.de/info/add-section.html