Yes, that’s right. It’s possible to jailbreak & unlock your iOS 4.1 on iPhone 4. I am not pretty sure whether it work’s with iPhone 3G/3Gs or not but it works on iPhone 4, at least it worked on mine. Please note that my baseband was 1.59.00. There are ways to update your iPhone 4 with iOS 4.1 while preserving your baseband. If you are not sure how to do that, just go to google & search for it you will find some article regarding this issue. If still you can’t find any, look here. Make sure your SIM card fits in iPhone 4′s mico SIM card slot. I am assuming you are done with that part.
So, if you think your ok with those requirements then you are ready to go. Let’s get started.
1. Jailbreak your iPhone 4 with “limera1n” which you can find here. If you don’t know how to jailbreak, read article from here. Please note that if you can’t see “Cydia” icon properly after jailbreaking, restart your phone, that should solve your problem.
2. Go to “Cydia” and click on “Manage” tab.
3. Now tap on “Sources” option.
4. Tap on “Edit” button and then on “Add” button.
5. Add the source exactly like this “http://repo666.ultrasn0w.com”.
6. Once the source is added search for “ultrasn0w 1.1-1″ in Cydia.
7. Now install “ultrasn0w 1.1-1″ app and restart your phone.
That’s all. Congratulations! now you have your iPhone 4 with the latest firmware (4.1) and ready to use. You can use any operator you want & you are not limited by AT&T only.
Here is the screenshots that I took from my iPhone 4, hope that will help you guys. If you like my post share it with your friends & families. Feel free to comment. Good luck.