this goes without saying...STAY AWAY FROM THESE UPDATES....they are only a trap that will close the hole/exploit that is used for the jailbreak for the perspective phones.

so you will not only loose your jailbreak,but no jailbreak=no unlock.

there is however some good news that is that there is a different exploit said to be found that will work for these updates,but is not ready or realesed yet.

so unless you are using att or verizon and dont care about being jailbroken stay away.

it is best to turn off the switch to automatically check for updates in itunes.