Rebug 4.21.2 to Rebug 3.55.4 (not working)

[Linxmas]

OK, so I have a problem, even a few.
So I have been on Kmew (at least I think it was it, pretty much sure) and made update to Rebug 4.21.2 via XMB. But later found out, that to get eid_root_key I need to be on 3.55 so I tried to update it via XMB to Rebug 3.55.4 but got error data corrupted etc. Instruction says, that its the way to do it if QA was enabled, which one I enabled with toggle_qa.
So by searching online I didn't find really the answer. Some say use Recovery Mode. But then I go to recovery and connect my PS3 Joystick I got this: "The System Software cannot be run correctly. Press PS button to try to restart system." etc. So I cant even get to Recovery Mode. By searching online I find just that this error get people who changed the hard drive , but I just changed CFW, not hard drive.
I just don get it, what happened? Maybe Rebug 4.21.2 CFW where installed badly? If needed I can try to update to 3.55 again and get exact error code.
The think, why I need to get to 3.55 is to get eid_root_key, because I don't have BD-ROM drive so I want to make Rebug 4.21.2 to run games discless in DEX mode.

[owen420]

well do you have a DEX or CEX console?

if its CEX, you install the 4.25 to 3.55 via xmb

then you run qa flag

then you install rogero 3.55 via recovery menu

then you can goto any cfw you want

[bitsbubba]

Is downgrade possible if you went to 4.21 without QA flagging first, from what I remember no, has anything changed