- Download GameCube ISO Tool Download
- Extract GameCube ISO Tool and copy gcit.exe to the same directory as the GameCube .iso files
- Open a text editor (ie Notepad) and paste the following command
for %%f in (*.iso) do gcit.exe "%%f" -q -b -d ".\%%f.trimmed.iso"
- Save the above Notepad document as gc.bat in the same directory as the GameCube .iso files
- Double click gc.bat
- Watch and wait