Firmware 5.00
Release Date: October 16th, 2008
New Features:
- [PlayStation Network] category has been added to the XMB to the right of [Network].
- PlayStation Store is now available under the PSN category
- Sign-up / Account Management icon is also available under the PSN category.
- You can now output video from PlayStation® format software to a TV in full-screen size (2000 & 3000 series only).
- You can now use video output cables that do not support video in progressive mode to output video from PlayStation® format software to a TV (3000 series only).
- [Title Display] has been added as an option under video settings.
- [USB Auto Connect] has been added as an option under system settings.
- [Backlight Auto-Adjust] has been added as an option under power save settings (3000 series only).
- Sleep timer (Sleep Timer) has been added as an option on the music control panel.
- Some 640x480 video file types are now supported.
- The background of the XMB (XrossMediaBar) screen has been redesigned.
- You can now use a full-size on-screen keyboard.


Firmware 5.01
Release Date: October 22th, 2008
New Features:
- Fixed a PS Store bug that would cause 8 GB or 16 GB Memory Stick Duo users to receive messages about not having enough free space, even when sufficient space exists. Don't confuse this with the way the PSP handles downloads (a 50mb demo requires 100mb of space, 50mb for the temp download and 50mb for the installation, once its installed the temp download is deleted).


Firmware 5.02
Release Date: November 20th, 2008
New Features:
- System software stability during use of some features, including PlayStation Store, has been improved.


Firmware 5.03
Release Date: January 20th, 2009
New Features:
- System software stability during use of some features has been improved.


Firmware 5.05
Release Date: never released online, only available on Idolmasters SP's UMD
New Features:
- Allows a PSP w/ Idolmasters SP to connect and unlock bonus content for the Japanese version of Home on the PS3.


Firmware 5.50
Release Date: April 20th, 2009
New Features:
- Information Board added to XMB - it displays news updates in a list with quick links to the PS Store and Internet Browser.
- Memory Stick improvements - create and access sub-folders on your Memory Stick PRO Duo for music, videos and photos. Also, the available space required to download a file from PlayStation Store to your Memory Stick has been reduced significantly.
- Internet search for games directly from the XMB - search the Internet for information about your PSP games by hitting while a game is selected to get the [Internet Search] option.
- Trend Micro trial - access a free trial of two Trend Micro services which enable phishing protection and the blocking of inappropriate "adult" sites.
- Go!Messenger icon removed because they shut the service down (affects only PAL region PSPs).


Firmware 5.51
Release Date: June 10th, 2009
New Features:
- System software stability during use of some features has been improved.


Firmware 5.55
Release Date: never released online, available on G.I. Joe: The Rise of Cobra UMD
New Features:
- Allows you to play G.I.Joe: The Rise of Cobra.