Our friend nickxab has posted the news in this forum here :
Downgrader for Firmware 3.55 to 3.41 released
And when nick released the news , it is reported that PS3 V3.55 downgrade is not available on slim , but now latest news has confirmed that both Slim and fat are working for downgrade now. so i update it in this post!
In this post , i would like to add some more info about it! And also with the tutorial and steps!
It has been confirmed that PS3 V3.55 downgrade is available on both FAT and SLIM consoles.
Notice: If your PS3 console is born with FWV3.50,PLS don't use this method!
(what is the meaning?i think it means if you bought the PS3 with V3.50 firmware and then update to V3.55, i am sorry , you can not use, you need to wait. if you didn't update to V3.55, you can just use a jailbreak item to do the downgrade, don't use this method either....)
THE SAME WARNINGS AND RULES APPLY:
You may want to download geo's 3.55-jb and install that and blackb0x ftp if you have not, it will be very useful for the next bit.
Blackb0x FTP server 1.2: Blackb0xFTP for 3.55 FW
If you have a fat PS3 with 256MB NAND you will need to back up your dev_flash folders, as you WILL LOSE BLURAY PLAYBACK. (on my FAT model i restored the DRL1 and DRL2 files in del_flash(2?) I did get to however keep all of my signed 3.55-jb homebrew, and it all works in retail mode except of course backup managers)
If you have a Small NAND SLIM or FAT console it would be a good idea to do one or both of the following:
In the XMB perform a system backup to save installed Homebrew you may have and gamesaves etc.. to an external device (i did this with my slim and it worked perfectly, all my installed signed homebrew from 3.55-jb works in retail 3.41 now)
make a COMPLETE backup of your HDD on your ps3 using ftp, although i dont think installed packages can be moved back over simply by ftp. i only tested the first method.
Download: Lv2diag_355 / PS3 3.55 Downgrade (3.41) / PS3 3.55 Downgrade (3.41) (Mirror)
PS3 downgrade step:
First , you need a jailbreak items , PS3 break, E3 card reader or use your android/iphone, or an ipod nano, if you don;t know how to use it, just search it in this forum!
1) Unplug or switch off your console and then switch back on or plug back in.
2) While still OFF connect your Jailbreak/Downgrade device and press POWER then quickly Eject, you PS3 console should turn itself off automatically
3) OPTIONAL - Turn your PS3 on to verify you are in Service Mode (you will see a big red box, you can't miss it) then turn your PS3 back OFF
4) Place the lv2diag.self (FILE 1) from the archive and the PS3UPDAT.PUP (3.41 FW) from the archive on the root of a usb device and plug into the rightmost port on your console (dev_usb0)
5) Power on your PS3 with the usb device in and have a coffee, it can take a few moments for the PUP to install, your PS3 will turn off automatically
NOTE: if your system seems unresponsive and the light just stays green for ten minutes or more you need to use a different usb stick. i've had sporadic results with several different sticks.
6) Power your ps3 back on, you should still be in service mode, check your FW version now to verify you have downgraded successfully. Turn Off
7) Remove previous archive files from usb stick and now place lv2diag.self (FILE 2) on the root of your usb stick
8) Place usb stick in rightmost port of your PS3 (dev_usb0)
9) Turn PS3 back on with usb in place, it should turn itself off very shortly after.
10) Turn your PS3 back on and go through the configuration again.
5C3B09C7FB0655D3F8852D3AA D778025 PS3UPDAT.PUP (3.41 FW)
099F33A7967F99E91C07E870F D78B3DB Lv2diag.self (FILE 1)
7A20BFDAE65EEFB47A4425DB1 B52DCDE Lv2diag.self (FILE 2)
Thanks mathieulh, solidpsycho, and everyone else.
you can watch the video in Nick's post here:
Downgrader for Firmware 3.55 to 3.41 released
Log: Notice "os version = 03.4100" 8 lines from the bottom.
manufacturing updating start
PackageName = /dev_usb000/PS3UPDAT.PUP
settle polling interval success
vflash is disabled...
boot from nand flash...
creating flash regions...
create storage region: (region id = 2)
format partition: (region_id = 2, CELL_FS_IOS:BUILTIN_FLSH1 , CELL_FS_FAT)
create storage region: (region id = 3)
format partition: (region_id = 3, CELL_FS_IOS:BUILTIN_FLSH2 , CELL_FS_FAT)
create storage region: (region id = 4)
format partition: (region_id = 4, CELL_FS_IOS:BUILTIN_FLSH3 , CELL_FS_FAT)
create storage region: (region id = 5)
create storage region: (region id = 6)
taking a while...
start Updating Proccess
Initialize elapsed time = 177 msec
Check UPL elapsed time = 97 msec
check Package Size
get package size elapsed time = 9 msec
start Updating Package
Update packages num = 28
Update packages total size = 160291533
Update Package Revoke list
read package revoke list package (576 bytes) elapsed = 66 msec
update package revoke list elapsed = 112 msec
Update Package Revoke list done(0x8002f000)
Update Core OS Package
read core os package (5182208 bytes) elapsed = 678 msec
update core os package elapsed = 1837 msec
Update Core OS Package done(0x8002f000)
Update VSH Package
sys_memory_container_crea te() success(id = 0xc0effffe)
Update VSH's package : 1/22
read vsh package (1841 bytes) elapsed = 18 msec
decrypt and verify vsh package elapsed = 27 msec
write vsh package elapsed = 7968 msec
compare vsh package elapsed = 0 msec
Update VSH's package : 2/22
read vsh package (4779240 bytes) elapsed = 616 msec
decrypt and verify vsh package elapsed = 305 msec
write vsh package elapsed = 2757 msec
compare vsh package elapsed = 489 msec
Update VSH's package : 3/22
read vsh package (1927089 bytes) elapsed = 258 msec
decrypt and verify vsh package elapsed = 129 msec
write vsh package elapsed = 680 msec
compare vsh package elapsed = 182 msec
Update VSH's package : 4/22
read vsh package (5498561 bytes) elapsed = 710 msec
decrypt and verify vsh package elapsed = 344 msec
write vsh package elapsed = 3384 msec
compare vsh package elapsed = 558 msec
Update VSH's package : 5/22
read vsh package (2010269 bytes) elapsed = 275 msec
decrypt and verify vsh package elapsed = 138 msec
write vsh package elapsed = 1028 msec
compare vsh package elapsed = 207 msec
Update VSH's package : 6/22
read vsh package (25301 bytes) elapsed = 25 msec
decrypt and verify vsh package elapsed = 29 msec
write vsh package elapsed = 1454 msec
compare vsh package elapsed = 10 msec
Update VSH's package : 7/22
read vsh package (7663270 bytes) elapsed = 988 msec
decrypt and verify vsh package elapsed = 393 msec
write vsh package elapsed = 15190 msec
compare vsh package elapsed = 587 msec
Update VSH's package : 8/22
Until now , the saftest way to jailbreak your PS3 is still use the jailbreak items to do it,my idea and what i am doing now is using my PS3 break V1.2 and PS3 game hdd to enjoy my game , then wait until it is 100% safe CFW come out.
If you have any questions about jailbreak your PS3, just submit your questions in this forum, we will help you to solve it.
Source: this guy has confirmed that it is available for both slim and fat styles!