I have done this PS3 PUP Unpacker & Decrypter v2.2 homebrew application tool (basically is an script that use other tools) a long time ago for easily unpacking a PlayStation 3 PUP file for those ...

While the custom firmware (CFW) hasn't been released to the public yet, GeoHot writes that it "can be installed without having to open up your PS3, just by restoring a custom generated PUP file ...

Video: Adding 'Install Package Files' on PS3 4.00 Dev_Flash Mod en PlayStation 3 › Scenethe PlayStation 3 XMB. Note: This modification does not allow the installation / usage of unsigned content ...

"This can be installed without having to open up your PS3, just by restoring a custom generated PUP file, but only from 3.15 or previous. It's possible this CFW will also work on the slim to ...