If you want more test elfs or selfs there happen to be some in sdk cell/target/images
I wish i could help more. New years resolution, learn at least two languages with a decent understanding, probably python and c++
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.