Hello Smoke,

FirmWare 05.14.02, can not be unlocked for other carrier, once phone upgraded to os4.1 its firmware automatically changed to 05.14.02.
There is no way you can down grade to previous firmware.
phone with os4.1 can be jailbroken with limera1n, carriee unlock is not possible as of now.
Dev Team is working on it but no solution as yet.