Wii Backup Manager is an excellent program that can manage FAT32, NTFS and WBFS drives and convert between ISO, CISO, and WBFS files. The guide below will show you how to add ISO images to your FAT32 drive. The program splits your ISO images into 4GB parts when transferring to a FAT32 drive as that is the maximum size.
1. Click on Drive 1 and choose your drive letter.
You will now see all games that you have on the Drive. Notice that there is information about your drive on the bottom.
2. After you have selected your drive in the Drive 1 tab, you can choose individual ISO, cISO or WBFS files or a folder to add to your drive.
Go to the Files Tab. Then choose "Add", then "Files" or "Folder".
3. Choose what games/images you want to transfer by using the check boxes. Then click on Transfer and choose Drive 1.