I've heard on irc there might be a fix. Apparently there are actually two copies of coreos on the ps3, one is run, and the other is a backup. But apparently that backup is never actually used (maybe in service centers?), some people have guessed that there might be a way to "flip a bit" and activate that 2nd coreos. All theoretical though.
This would require a nand/nor flasher.
Correct me if i'm wrong about any of that.
Oh, yeah, don't expect a software fix anytime soon, maybe ever. Hardware is the way to go.
STOP! Before you ask questions... READ the first post! RTFFP = Read The F*cking First Post
Yes, A 3.55 "jb" (cfw) is available, no >3.55 "jb" or cfw yet.
Yes, A 3.55 downgrade is available. But not to lower than stock firmware! (What it came with)
No >3.55 downgrade is out there yet.