I screwed up a 3gs last year, installing IOS 5, so put it into a shop who restored it back to IOS 4.1 and BB 06.15.00, JB'ed it and ultras0w to unlock it.
I would like to upgrade it to IOS 6.1 now to JB and ultrasn0w it.
What will happen to the baseband if i do the official upgrade through iTunes?
If that is going to be an issue , can I use redsn0w to preserve the 06:15.00 baseband?
does ultrasn0w work on 3gs phones on 6.1?