Hold+ is the ultimate companion to the PSP’s music player. It adds useful features and gives you TWICE the battery life when used properly.

It does the following when the Hold switch is enabled:
* Switches off the LCD screen and backlight.
* Underclocks the CPU to 60MHz
* The original screen brightness and clock speed are restored when the Hold switch is released.
* Prevents the PSP from going into suspend mode if you accidently push the power switch too far when turning off Hold mode.
* Allows complete operation of the PSP controls with the display turned off.
* Turns off LEDs in hold mode.
* While in hold mode, allows the use of Left, Right, LTrigger, RTrigger, Volume and Start buttons, if you hold the Select button first. Useful to skip songs, pause etc.

Additional Features:
* Enables the 5th brightness level on PSP Slim.
* Increases the vertical scrolling speed of Music player by around 50% (scroll 300 songs in 10 seconds).

Changes:

Optimized Code.
Proper fixed to prevent any chance of accidental suspend when coming out of hold mode due to pushing switch too far.
LEDs do not blink every 30 seconds anymore.

http://forums.qj.net/psp-development-forum/146894-release-hold-v3-7-battery-saver-plugin.html