Le débrick est possible mais attention, vous devrez acheter un e3 ainsi qu'un dongle de downgrade ainsi que le CFW Rogero 3.55 "normal" CEX.
Vous n'aurez PAS besoin d'avoir déjà un dump de votre nor avant d'avoir installé le CFW 4.21.
Débrick
- Pour se faire, vous devrez suivre le début du tuto de downgrade en 3.55 avec E3 jusqu'à la fin de la 3eme partie (vérification des dumps sur votre pc).
- Une fois que vous avez vérifié 10 fois que votre dump est 100% correct, vous devrez utiliser PS3_Nor_Dump_Auto_Patcher_v0.01.rar sur votre dump.
- Suivez ensuite le reste du tuto et downgradez avec le CFW Rogero en 3.55.
Notes:
I didn't receive any Brick report from any FAT PS3 that updated to CFW4.21, so it seems FAT consoles are not being affected by the bug.
Apparently only the last downgradable Slim models are affected (CECH-25xx with Datecode 1A and base FW version = 3.50)
I also know that there are also few Slims that bricked with model CECH-20xx but 90% of the reports were model (CECH-25xx with Datecode 1A and base FW version = 3.50).
The Brick may be caused by the boot-loaders not being written correctly into the NOR during the Update process.
Please note also that all the above info may not be 100% accurate, things are still being worked on so nothing is confirmed at all and I don't promise anything about an updated CFW.
CECH 2504B BRICKABLE Slim
CECH 2501B BRICKABLE Slim
CECH 2501A BRICKABLE Slim
CECH 2511A ACCEPTABLE Slim
CECH 2004A ACCEPTABLE Slim
CECH 2504A ACCEPTABLE Slim - possible bricks
CECH 2011A ACCEPTABLE Slim
CECH 2001A ACCEPTABLE Slim
CECH 2104A ACCEPTABLE Slim
CECH2004B N/A N/A
CECH 2101A ACCEPTABLE Slim
CECH 2004B ACCEPTABLE Slim
CECH-2504A BRICKABLE Slim
CECHJ 04 ACCEPTABLE Fat
CECHL 01 ACCEPTABLE Fat
CECHG 01 ACCEPTABLE Fat
CECHL 11 ACCEPTABLE N/A
CECHK 01 ACCEPTABLE Fat
CECHL 04 ACCEPTABLE Fat
CECHK 11 ACCEPTABLE Fat
CECHH 01 ACCEPTABLE Fat
CECHG 04 ACCEPTABLE Fat
Note: This isn't set in stone. Have a hardware flasher or know how to recover even if your console model is acceptable. Make a multiMAN NAND/NOR backup and ensure QA flags are set!!! Hope you have a great time!
Source : http://www.ps3news.com/ps3-cfw-mfw/ps3-brick-recovery-procedure-from-rogero-cfw-4-21-to-cfw-3-55/