Tutorial written by Black_Skull, translated by KoubaK, vb_master redid banner and added rev. 2 and 3 information. Updated to 2.71 SE-B, FAQ by Hardrive.
What until couple of days ago, was just a rumor, has become reality, once again, thanks to Dark_AleX, Harleyg, and Mathieulh. This allows us to have 2.71 firmware, with the 1.50 firmware functions. Yes, you not seeing things. It seems that 1.50 firmware no longer have a future.
//The flashing is a delicate process, since we are going to format the flash memory(flash0) of the PSP and install a "new firmware", so make sure you battery is fully charged, and the AC adapter is connected to the PSP.
//This guide will assume you have a 1.50 PSP. If you have 2.71 SE-A, read the FAQ below to learn how to uninstall it. If you have any other firmware, downgrade to 1.50
// DO IT AT YOUR OWN RISK!, Neither BlackSkull for making this tutorial, Dark_Alex, Harleyg, and Mathieulh for creating this Custom Firmware or any other person will take responsibility for any failure resulting into a brick.
//Dark_AleX's 2.71 SE-B: http://dax.lan.st/271_SEB.RAR
//1.50 Update Eboot: http://dl.qj.net/dl.php?fid=163
//2.71 Update Eboot: http://dl.qj.net/dl.php?fid=8046
Installing the Files
//Download the 2.71 SE-B .rar file, and un-rar the files from the NEWINSTALL folder to the ROOT of your Memory Stick (where PSP and MP_ROOT folders are). Navigate to X:\PSP\GAME\seupmaker\ (where X is your PSP's drive letter). Rename the 1.50 Update Eboot to 150.PBP and copy it to the seupmaker folder. Rename the 2.71 Update Eboot to 271.PBP and copy it to the seupmaker folder.
//When asked, overwrite the PSP and the GAME folders.
Now, In the PSP, Go to GAMES > Memory Stick and start the SE UpdateMaker.
A bunch of white letters will come up.
Once it finish (takes about 3 or so minutes), It will return to the XMB, Connect the PSP to the USB port, and now a new file in PSP/GAME/SEUPDATEMAKER, named DATA.DXAR, should be there. The update maker no checks the DATA.DXAR, so there is no reason to check it yourself. Copy the file DATA.DXAR to the directory "PSP/GAME/271SEFLASHER".
Installing 2.71 SE-B
//TAKE OUT ANY UMD THAT IS IN THE DRIVE!!!
Connect the PSP to the USB port, and make sure your battery is at least 75% (100% recommended) and plug the AC adapter.
Start the application, named "2.71 SE flasher".
It will display some pink words, just press "X", and it will start flashing your psp, it will display a percentage.
When it finish, it will display "Done...rebooting..." , and will restart to a new firmware: 2.71 SE-B.
Now You can Format the Memory Stick.
Recovery MenuNow turn your PSP off, and turn it back on, holding the 'R' button. The PSP will enter recovery mode, don't panic. Scroll to configuration, and press 'X'. Scroll to Game folder homebrew, and press 'X' until it displays "(currently: 1.50 Kernel)". Optionaly, you may disable hide corrupt icons and disable SCE logo.
Loading Homebrew in 2.71 SE
//To Load Homebrew, as you used to in 1.50, you should put the homebrew kxploited or not, in the directory PSP/GAME (this one you create), and viola, you're done.
**APPLICATIONS LIKE XFLASH, DO NOT WORK!**
//To Load Homebrew, made for HENC just place them in PSP/GAME271.
//You MUST have an ISO folder in the root of your memory stick, and a GAME and GAME271 folder in the PSP folder of your memory sitck
Updating 2.71 SE-B to SE-B' or SE-B"//Download the patching files here: SE-B' or SE-B"
//Make sure your PSP is plugged in.
//Simply put drag the files to your memory stick, and launch it from game menu.
//The patcher will patch SE-B to SE-B' or SE-B" depending on which you picked.