I have a Wiikey 1.9b firmware, and a NTSC Wii 3.0U firmware. I've attempted to burn the Config Disc 1.3 .iso three times, all resulting in DRE's. I am using high-quality media that has worked for both Wii and Gamecube backups as well as the 1.9b Update Disc so I don't believe that is a problem.