If you unlocked your iPhone using ultrasn0w 1.1. you might have noticed that your battery drains out pretty quickly. They tweaked a few things and this update suppose to fix that issue. You can update ultrasn0w via Cydia.
baseband 01.59 unlock
Posted inHOWTO
HOW TO: Unlock iPhone 3G/3Gs And iPhone 4 With Ultrasn0w
YES! iPhone 4 unlock is finally here. The iPhone DevTeam just released their new version of ultrasn0w which will unlock your iPhone 3G/3Gs and iPhone 4.
FSM EXCLUSIVE DEAL