Voilà le manuel pour ceux qui n'on pas de compte sur maxconsole :

[i]Epsilon is broken into two parts, the bootloader and the BIOS. The bootloader is
flashed to UP memory once, then to install or update the BIOS the bootloader
recovery menu is used. You shouldnt need to flash via the UP tool again once
the bootloader has been initially installed, making things easier for customers.

To install:
-----------

1) Program "epsilonBootloader1.0.flash" to UP using the flasher tool
2) Copy EBUPDATE.BIN into the root directory of your memory stick. This can
be done with a card reader, via the epsilon recovery menu or via the PSP OS.
3) Turn on the PSP, it will enter the recovery menu since no BIOS is installed.
4) Select "Update Epsilon BIOS"
5) If you dont have 2.71 installed in PSP onboard firmware you will need to do
so. This can be done with the recovery menu, place the update EBOOT in the
standard place on the memory stick (/PSP/GAME/UPDATE/EBOOT.PBP) and select
"Launch Firmware Updater" from the recovery menu. This can be used to both
upgrade and downgrade the PSP onboard firmware using Sony's own updaters.

NOTE: To forcefully enter the recovery menu, hold SELECT+START while turning
the PSP on.

To unbrick a PSP:
-----------------

1) Place a NAND flash image of 1.00 or 1.50 firmware (same format as used by
UP flasher tool) in the root of the memory stick with the filename
"nandImage.flash".
2) Enter the recovery menu and select "Restore onboard NAND"

Running homebrew:
-----------------

1) Copy EBOOT's to the normal location (/PSP/GAME/). Both 1.0 and 1.50 types
are supported.
2) Execute them from the 2.71 shell

Running ISOs:
-------------

1) Copy ISO files or compressed EZIP (use the supplied tool) into /ISOS on the
memory stick.
2) The games will appear in the same menu where homebrew is lunched from
(the Memory Stick->Game menu). Simply launch them as you would with homebrew.

NOTE: Each time the contents of the ISOS directory are changed a cache file
must be updated which will cause a slight delay when entering the
Memory Stick->Game menu./i]