The video above supposedly shows a Playstation 3 booting a game from the hard drive by booting a legitimate game from disc. There aren't many other details besides a comment that backing up Blu-ray discs takes a lot of space. So, if this does actually work, it's doubtful we'll see much piracy because of it.
[via PS3Scene]
http://www.hackaday.com/2008/08/16/ps3-hacked-for-backups/