I have a friend who recently bought an iPhone 3GS off from craigslist and asked me if I could help him to jailbreak and unlock it. The phone was 3GS, 4.1 with baseband 5.15.04.
After checking around, I noticed that baseband 5.15.04 was unlock-able and in order to have the phone unlocked, we had two options: either to upgrade the baseband to 6.16.00 (without GPS capability) or to buy an unlock sim.
My friend decided to go for the baseband upgrade. I tried numerous guides using pwnagetool but it simply didn’t work. Basically, I was able to generate a custom .ipsw file and used iTunes to restore. The restoration completed successfully and the iphone was jailbroken but the baseband wasn’t upgraded. It kept staying at 5.15.04.
Finally, here is a working method to successfully upgrade iphone 3GS baseband from 5.15.04 to 6.15.00.
- Redsn0w 0.9.6 Beta 5
- iOS 4.1 IPSW
- There is no need to download iPad IPSW, Redsn0w will fetch the iPad baseband off from its servers and iTunes is not required for this method. Pretty good.
- Download Redsn0w 0.9.6 Beta 5 here (mac or windows) and iOS 4.1 IPSW here
- Start Redsn0w 0.9.6b5 and point it to iOS 4.1 IPSW
Note: if you use an older version of Redsn0w, you may get unrecognizable IPSW error. Make sure you use Redsn0w 0.9.6 Beta 5.
- Once Redsn0w recognized your iOS 4.1 ipsw => click next, you will see a screen with several options => check on “Install iPad baseband” (this will trigger the baseband upgrade) => then choose Yes.
- Now Redsn0w will ask you to put your iPhone in DFU mode. Simply follow the steps provided by Redsn0w to go into PFU.
- Simply follow the next few steps to finish. Be patient when it download the baseband. It may take a few minutes but it will be done eventually.
- That is pretty much it. Once the phone boots up, follow the steps below to unlock your jailbroken iPhone.
How to unlock iPhone 3GS baseband 6.15.00
- If you have followed the steps above, it is now very easy to unlock your iPhone. Simply start Cydia
- Choose “user” mode
- Upgrade any packages if required
- Now click on the “Manage” button
- Click on “Sources” => the unlock source should already be there for you
- Click on repo666.ultrasn0w.com
- Click on ultrasn0w
- Click on Install on the top right => once installed, reboot your iPhone => once rebooted, reboot your iPhone once more
- Now insert your SIM if you have not done so, your iPhone should now be unlocked. If the signal says “searching…” just be patient, it will be done in just a couple of minutes.