Originally Posted by itskamel
im not totally sure about the downgrade process as i have never done it. but i think that you should make sure rebug is qa first. there is a option in there. then use the 999 downgrader.
hope i won't brick my ps3
ADD: So here is it, i take my chances.
1. From 4.21 REX, install 9.99 downgrader on XMB.
2. From 9.99 REX, i enable QA in REBUG Toolbox. dunno if it's necessary but to make sure that the PS3 is in QA. never did the button combinations.
3. Put the PS3 in recovery mode, install 3.55 OFW.
4. Put the PS3 in recovery mode again, install 3.55.3 REX.
5. Restore my user's backup from XMB so I can use my savegames again.
Console: Sony Playstation 3 [CECH-2012B]
Firmware: REBUG 3.55.3 REX