PlayStation Jailbreak was the first Universal Serial Bus chipset that allows unauthorized code execution, such as homebrew, on the PlayStation 3. It bypasses a system security check using a memory exploit which occurs with USB devices that allows the execution of unsigned code. One of the most popular pieces of homebrew software used with the device is Backup Manager, which allows users to copy game titles from the optical media to the hard drive of the PlayStation 3. Backup Manager can also be used to run homebrew applications that are created to run in the console's native mode.
Multiple devices to perform code execution exist, such as the open sourced versions (e.g. PSgroove, PSfreedom). Most of these only work on PlayStation 3 system software v3.41 or lower as PlayStation’s System Software v3.42 patches the mod chip exploit on the console. The creators of PS3 Jailbreak also released PSDowngrade which enables downgrading of PlayStation 3's System Software to v3.41 (Or lower) from v3.42, v3.50, and v3.55.
The jailbreak was in .PUP format and allowed users to have access to their PlayStation’s internal HDD and run homebrew. The use of backup managers on v3.55 was not possible until the 19th of January 2011 when Kmeaw (an Eastern European hacker) released his 3.55 custom firmware which allowed the PlayStation’s BD drive to be emulated. (Wikipedia)
Ps3 console now be on the latest jailbreak CFW on v4.50. Please upgrade your ps3 to be able to play the latest games.enjoy it!!