Yeah, the " Service Mode" .

This has been the work of the alliance of a lot of developers externally known as " C+D" : Nem, joek, Fanjita, Chris, jim, psp250, ditlew, Skylark, Dark_AleX, mathieulh, tyranid, adrahil and Booster.

The battery lets to downgrade any firmware version (including those that Sony releases in the future), and to unbrick bricked psp' s (whatever bricked by software psp, not only the ones bricked by that retard of Serafin), in all current hardware. Of course, we cannot be sure about future hardware, but the Firmware Update game has finally come to the end for all current psp' s.

PANDORA' S BATTERY
=================

A universal PSP unbricker/downgrader by the Prometheus project, also
known as Team C+D.

REQUIREMENTS
- A spare PSP Battery. Any make will do. Using a spare is best, as it
will not be possible to boot the PSP in its normal state with the
modified battery.
- A spare Memory Stick Pro Duo of less than 4Gb. (256Mb should be
enough for all applications).
- A PSP with a Custom Firmware such as OE, M33 or WC, or a PSP with
the 1.5 original kernel.

INSTALLATION PROCEDURE
- Connect the PSP to the PC with the Memory Stick inside via the USB
Connection.
- Format the Memory Stick using any utility.
- Use mspformat to format the Memory Stick logically.
- Remove the Memory Stick and disable the USB connection.
- Connect the Memory Stick again via the USB connection of the PSP.
- Manually create the PSP/GAME (optionally PSP/GAME150) folders on the
Memory Stick.
- Copy the " battery" and " installer" programs to the PSP/GAME
(optionally PSP/GAME150) folder.
- Copy the 1.50 official updater as UPDATE.PBP to the root of the
Memory Stick.
- Remove the Memory Stick and disable the USB connection.
- Run " installer" through the firmware on the PSP. This application
will create the firmware files on the root of the Memory Stick, as
well as msipl.bin.
- Connect the Memory Stick again via the USB connection of the PSP.
- Execute " msipl" application on the PC with the msipl.bin to write
the IPL to memory stick.
- Remove the Memory Stick and disable the USB connection.
- Execute " battery" application on the PSP to modify the battery.
- Congratulation, you are now in posession of a " Magic Memory Stick"
and a " JigKick Battery" .

USAGE
- Insert Memory Stick into the PSP
- Remove power cord and insert the JigKick Battery into the PSP.
- A menu appears when the PSP boots. Follow the onscreen information
and instructions.

NOTES AND RESTRICTIONS
- The firmware in the Memory Stick is not a full 1.50, but a minimal
subset. Therefore, not all applications (such as flashers, or
recovery apps) will load.
- Only Memory Stick Pro Duo are compatible. Memory Stick Duo
(e.g. 32MB sticks) are not supported.
- The IDStorage cannot be totally restored, as there is no known way
to regenerate it properly.
- It is strongly RECOMMENDED to make a flash dump of the PSP before
any downgrading operation.
- There might be a BSOD at the end of the downgrade. This is normal,
and happens on the standard downgraders.
- All hardware revisions known at this day are supported.
- This release contains no Sony-copyrighted material. All required
Sony data is generated from the v1.50 update files.