Hia i had this problem when i tried connecting to 3.
i solved this by going back on to red sn0w after the update and went into jailbreak and just tick install band. one your phone turns back on after it has re installed the flash band it should work x
Is your phone used on official carrier or was it JB and unlocked before?
If you updated a software unlocked iphone to stock firmware without thinking you lost your unlockable baseband. 05.16.02 cannot be unlocked.
You might be stuck having to install the ipad bb if you need it unlocked but that's not a good idea and comes with many sides.