Actually for BootOS it uses an official kernel, which doesn't have full vram access. So you just have to compile grafs one and you have full vram access, which makes it run perfectly. Seriously, since I don't play much pc games anymore, linux on the ps3 actually runs well enough to use it as a main computer.
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.