Warning: I shall and WILL NOT be responsible for anything that happens to your Playstation Portable System. You shall take all responsability for any side effects or anything that goes wrong.
It is recommended to use a formatted Memory Stick.
Ok. Here is what everyone is waiting for.
Any Firmware can do this from 2.80 and under, (Not 3.03, You must DOWNGRADE, Any SE or OE will work as well)
The first downloadable file is the 3.10 OE-A eboots.(a.k.a updatemaker and flashers). The 2nd and 3rd will be the 3.10 update and the 1.50 updates.
Note: The updatemaker will take a while to make the files so don't worry if its taking to long.
1.Download the files.
2. Extract the 2 Sony updates (1.50 and 3.10) and rename the eboot files
( 1.50 Sony Update: eboot.pbp---> 150.pbp
3.10 Sony Update: eboot.pbp---> 310.pbp)
(Note: DO NOT CHANGE BY ANY MEANS THE PBP. EXTENSION FILE, the file will not work if pbp is changed)
3. Place the newly named files in the following place.
( 150.pbp and 310.pbp in to updmaker NOT updmaker%)
4. The updmaker and the updmaker% shall be place accordingly to your FW.
( 1.50 ---> 2.80 : GAME folder
2.71 ---> 3.03 SE/OE : GAME150)
5. Run the 3.10 Update maker.
6. If all worked fine your PSP should have made a DATA.DXAR file.
7. Now Go to USB mode and extract the DATA.DXAR file from the updmaker folder, and place it in the 3.10oeflasher,(again not %).
8. Before you place the 3.10oeflasher into your mem stick, format it again.
9. Place the 3.10oeflasher and the 3.10oeflasher% in the GAME or GAME150 (just like above depending on your firmware)
10. This is the moment of truth... Just pray your psp pulls through.
11. If all works fine you should have a brand new 3.10 OE-A PSP.
Enjoy!
Thats the 3.10 update.
MaxConsole Forums
1.50 Sony Update
http://www.psp-hacks.com/download.php?id=4
3.10 Sony Update
http://www.psp-hacks.com/download.php?id=1037
TWOOT 
Linear Mode
