For some older or simpler level mods, you may need to extract the entire game ISO and manually replace internal files: Right-click the game in Dolphin, go to Properties > File System , and select "Extract Entire Disc" Replace the files in the extracted/data/files directory with those from the mod folder (e.g.,
Ensure you are using a recent Beta or Development version (not the stable 5.0 version, which is outdated). new super mario bros wii mods dolphin install