Wii games are originally stored in ISO format, which can be up to 4.3GB regardless of how much actual data is in the game.
The most reliable way to handle these files is by using 7-Zip for extraction and Wii Backup Manager for conversion. 7z to wbfs converter
: Always ensure your USB drive is formatted to FAT32 or NTFS before using conversion tools to transfer games. Wii games are originally stored in ISO format,
: Go to the Files tab, click Add , and select the .iso file you just extracted. 7z to wbfs converter