If you are on baseband 05.14.02 on your iPhone 3G Ultrasn0w won’t help you. You need to update your baseband using this tutorial for carrier unlock. We will use the iPad Firmware file to update the baseband and jailbreak using PwnageTool. Instructions and screenshots after the break.
We received requests from several readers to provide unlock solutions for iPhone 3G with baseband 05.14.02. This guide will work for both iOS 4.1 and 4.2.1 so no matter which firmware you have you can follow these instructions to jailbreak and unlock iPhone 3G.
Steps to Jailbreak iPhone 3G:
Launch PwnageTool and choose Expert Mode.
Select iPhone on the next screen.
When asked to Browse for IPSW, select the iPhone 3G firmware version 4.1 or 4.2.1 and click on the blue arrow to proceed.
On the next screen you will be asked if you want to update to iPad baseband. Click on YES.
Now Browse for iPad IPSW and click next. Rest of the jailbreaking procedure is simple and same as previous PwnageTool procedures.
Select Activate the phone if you are not using official carrier.
Click on Build and then on Next.
Save the custom .IPSW file. Normally takes around five minutes to complete. PwnageTool will ask you to enter your password once before building the custom file.
Now the major work is done. Connect iPhone to your computer. It needs to be put into DFU mode before we restore it in iTunes.
When PwnageTool asks you if your iPhone has been Pwned before, select No. Press iPhone buttons in the sequence showed on screen. In case you fail in first attempt, don’t worry and patiently try again.
Once iPhone is in DFU Mode open iTunes and press Alt/Option + Restore and point iTunes to custom IPSW file that we just made.
In around ten minutes your iPhone should restart with a jailbroken iOS 4.2.1 firmware or 4.1 in case you opted for it. Proceed to read How to Unlock iOS 4.2.1 using Ultrasn0w to unlock your iPhone 3G using Ultrasn0w.
Questions? Feel free to comment!