Unlock Apple iPhone 3G iOS 4.1 (tips, tools, repair, fix, downgrade, firmware)

One of our customer forwarded the following method of unlocking his iPhone 3G iOS 4.1, which he ultimately killed and bricked his iPhone.  Please DO NOT use the information to unlock your phone as it will void your warranty and certainly will brick your phone!

The PwnageTool for Mac OS X have been released now and you could use to jailbreak your iPhone 3G on iOS 4.1 while preserving the baseband so that you could unlock iPhone 3G 4.1 iOS. The old version of Ultrasn0w, that is version 1.1-1 could be used to unlock iPhone 3G 4.1 iOS. Here are the steps to do it.
NOTE: You could now use the guide given here instead of this.
How to Unlock iPhone 3G iOS 4.1
1. Jailbreak iPhone 3GS on iOS 4.1 using the guide given here.
2. Launch Cydia.
3. Choose the  Manage tab at the bottom.
4. Choose the Sources option.
5. Tap the Edit button and then on the Add button.
6. Then add the source

7. After the source is added, search for ” ultrasn0w 1.1-1 ” in Cydia.
8. Install the Ultrasn0w 1.1-1 app to unlock iPhone 3GS 4.1 firmware.
9. Restart your iPhone 3GS.
That’s it! Now you have an unlocked iPhone 3GS running iOS 4.1.?