From what I understand about DVDs, the key is stored in the lead-in, which is inaccessible to DVD burners. Blank DVD media simply has the lead-in all zeroed out so you can't duplicate the CSS key or Xbox digital signatures. Correct me if I'm wrong, but this is how I understand it.Joeymad said:Since there is no way to burn this digital signature onto backup copies (I'm not sure why), the original Xbox bios sees that there is no signature and doesn't allow it to run.