If you have accidentally updated to 3.1.3 from 3.1.2 your iPhone 3GS or iPhone 3G would have been upgraded from baseband 05.11.07 to 05.12.01. Many people who have accidentally updated to 3.1.3 have got the baseband upgraded to 05.12.01 and are waiting for the unlock tool. Now the iPhone Dev-Team has updated the unlocking tool ultrasn0w to “Ultrasn0w 0.93” which can be used to unlock 05.12.01 baseband. Ultrasn0w 0.93 can be used to unlock iPhone baseband 05.12.01 with iPhone OS 3.1.3. Ultrasn0w 0.93 can be used to unlock iPhone 3GS and iPhone 3G on 3.1.3 with 05.12.01 baseband.

Important Points to Note about Ultrasn0w 0.93

• UltraSn0w 0.93 can unlock basebands 04.26.08, 05.11.07, 05.12.01 and 05.13.04.
• Ultrasn0w 0.93 can unlock firmware iOS 4 and iPhone OS 3.1.3, 3.1.2, 3.1, 3.0.
• iPhone 3GS (If used Spirit for first Jailbreak) should stay away from iOS4.
• Your iPhone 3GS/3G must already be jailbroken.

If you haven’t yet jailbroken your iPhone then read below guides

Download Sn0wbreeze 3.1.3 v1.5.2 to Jailbreak iPhone 3GS and 3G With 3.1.3 Firmware
Jailbreak iPhone 3GS/3G/2G on 3.1.3 Firmware With PwnageTool

Procedure to Unlock iPhone 3GS and 3G on 3.1.3 With 05.12.01 Baseband Using Ultrasn0w 0.93

1. Launch “Cydia” and go to “Manage” section present on the bottom of the screen
2. Touch on “Sources” and then on “Edit” and finally on “Add”.
3. Add the Cydia URL as repo666.ultrasn0w.com and touch on “Add Sources”.
4. Once the Source is added to Cydia, hit the return to Cydia button at bottom of the screen and then Done button
5. Now search for “Ultrasn0w 0.93″ and install it.
6. Once the installation is completed just reboot your iPhone and it will be unlocked!