convert tethered jailbreak to untethered on 5.1?

[lokster]

im currently on 5.1 on my iphone 4

is there a way to get untethered jailbreak on it WITHOUT having to update to 5.1.1? kind of like a corona add on. or do i have to update and restore fresh and then jailbreak on 5.1.1? i dont want to update and just keep my files, ive got too much tweaks going on

 

[labman]

maybe latter but nothing now.