This simply isn't possible at this time.
The main game eboot is 3.60, so we can't decrypt it, and mod it.
The game update eboot allowing us to play it is npdrm encrypted, which can't be decrypted, so we can't mod it.
So no. This is not possible at this time.
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.