Some users have reported significant loss of GPS signal after upgrading to baseband 06.15.00. iPhone Dev team has also confirmed that though baseband 06.15.00 is capable of GPS, it might require further hacks.
Activate iPhone Without Official Carrier SIM And Also Fix Poor Battery Life Issue After Unlocking Using SAM
We had reported yesterday that iPhone users who hadÂ unlocked their iPhone using a combination ofÂ PwnageTool orÂ Redsn0w to update baseband to 06.15.00 andÂ Ultrasn0w 1.2 forÂ iOS 4.2.1 were observing poor battery life.
Developer @sbingner (author of popular jailbreak app – TetherMe) has figured out a way to fix the issue. He has released a jailbreak app called SAM (Subscriber Artificial Module). It tricks your iPhone and iTunes into creating legitimate activation tickets even though youâ€™re unlocked with Ultrasn0w.
If you are observing poor battery life after unlocking your iPhone using a combination of PwnageTool or Redsn0w to update baseband to 06.15.00 and Ultrasn0w 1.2 for iOS 4.2.1 then you are not alone as some readers have reported the issue.
After releasing PwnageTool for Mac earlier iPhone Dev Team has released Redsn0w to allow users to flash their iPhone 3GS and iPhone 3G with iPadâ€™s exploitable 06.15.00 baseband so that they can use Ultrasn0w 1.2 to unlock their iPhone.
Apple had patched the exploit that allowed users to unlock their iPhone in iOS 4.1 released on September 8 so it has been a long wait for users who wanted to software unlock their iPhone to use it with any carrier.
Ultrasn0w For iPhone 3GS, iPhone 3G Will Unlock All Basebands, Including iOS 4.2.1 Baseband 05.15.04
Before they go on to explain the current situation, they have advised users to avoid updating to iOS 4.2.1 until they release tools for iOS 4.2.1.