Wii Backup File System ) is the standard file format for playing Wii games from USB drives or SD cards on modded consoles. It is widely preferred over the original ISO format because it "scrubs" the unnecessary "junk" data used to fill up physical discs, resulting in significantly smaller file sizes without losing game quality. Essential Tools for WBFS

Before WBFS, loading backups on a modded Wii meant burning dual-layer DVD-R discs (for a console that originally read pressed DVDs). This was unreliable: DVD-R lasers aged quickly, and many Wii consoles had trouble reading burned media.