TheArtificer has released a public Beta firmware and Ripp3r software over at the k3yforums.com featuring the new 'No Keys' ISO handling for 3k3y (PATA). With this firmware no drive key is needed, in other words no downgrade required, you can now install 3k3y in a fat PS3 with latest original firmware (4.46) from Sony. This hack requires one original disc (any game will do) which is used with the Ripp3r software and a matching IRD (Iso Rebuild Data) file to resign the backups you wish to play. The chosen original game disc needs to be inserted while playing your backups from hard drive. In this beta release you need to decrypt and re-encrypt the ISO to resign on the computer, but this handling will be optimized in the next release effectively eliminating the decryption step.
There seems to be some confusion out there about what is required when using 3k3y to play backups on a PS3 without having the drive key, so I'll try to explain that without the technical details involved in the process. Pick one original game disc, any disc will do, find the matching IRD file for that game, done! You are now set to play any backup out there using this one single original game. The other requirements are just software steps to create the ISO files to load from hard drive.