Download here and follow the instructions... worked for me.
https://github.com/FIX94/Nintendont
Quick Installation:
- Get the loader.dol, rename it to boot.dol and put it in /apps/Nintendont/ along with the files meta.xml and icon.png.
- Copy your GameCube games to the /games/ directory. Subdirectories are optional for 1-disc games in ISO/GCM and CISO format.
- For 2-disc games, you should create a subdirectory /games/MYGAME/ (where MYGAME can be anything), then name disc 1 as "game.iso" and disc 2 as "disc2.iso".
- For extracted FST, the FST must be located in a subdirectory, e.g. /games/FSTgame/sys/boot.bin .
- Connect your storage device to your Wii or Wii U and start The Homebrew Channel.
- Select Nintendont.
Also try using a External HDD because according to the site, SD card and USB flash drive causes problems.
Notes
- The Wii and Wii U SD card slot is known to be slow. If you're using an SD card and are having performance issues, consider either using a USB SD reader or a USB hard drive.
- USB flash drives are known to be problematic.
- Nintendont runs best with storage devices formatted with 32 KB clusters. (Use either FAT32 or exFAT.)