Apple Inc. is expected to release an major update to the iPhone firmware making jump to version 3.1 - as always if you are using an unlocked iPhone do not risk updating to iPhone OS 3.1 via iTunes as the new update is still not confirmed unlockable by the iPhone Dev Team and could potential mean risking your phone locked to the original carrier forever as for most people once baseband firmware gets updated it cannot be reverted back to a previous version.

Luckily, you can still enjoy the new update without upgrading the baseband and to do that all you need to do is to use PwnageTool application instead of iTunes to update the firmware as PwnageTool lets you update iPhone's main firmware without touching the baseband firmware, this ensure that you can still use ultrasn0w hack to keep your iPhone's working with unsupported carriers.