How to Update baseband 5.15.04 to 6.15.00 for iPhone 3GS

by Stephen on September 20, 2011 · 110 comments

in iPhone Unlocks

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.

Tools used:

  • 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.
Step by step:
  1. Download Redsn0w 0.9.6 Beta 5 here (mac or windows) and iOS 4.1 IPSW here
  2. 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.
  3. 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.
     
  4. Now Redsn0w will ask you to put your iPhone in DFU mode. Simply follow the steps provided by Redsn0w to go into PFU.
  5. 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.
  6. 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

  1. If you have followed the steps above, it is now very easy to unlock your iPhone. Simply start Cydia
  2. Choose “user” mode
  3. Upgrade any packages if required
  4. Now click on the “Manage” button
  5. Click on “Sources” => the unlock source should already be there for you
  6. Click on repo666.ultrasn0w.com
  7. Click on ultrasn0w
  8. Click on Install on the top right => once installed, reboot your iPhone => once rebooted, reboot your iPhone once more
  9. 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.
Hope this helps!!!

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