Hopefully Portal 2 updates will be 3.55 or less... If it's 3.56 we can add 3.56 keys to 3.55.
If you look at the Portal 2 eboot, you'll notice it was built with the 3.50 sdk, really hoping the updates are signed with those keys...
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.