iPhone 3GS and iPhone 4 owners, updating firmware the regular way, via itunes, will change your baseband. And you won’t be able to unlock your phone afterwards. If you only need the jailbreak, you have nothing to worry about, as this doesn’t affect you. But if you need an unlock after a firmware upgrade and your baseband can be unlocked right now, update with the help of our custom firmware, which will preserve your old baseband! More information in the members section.