Downgrade iPhone 3G/3GS Baseband 06.15.00 With Redsn0w 0.9.14b1 To Get Unlock & Fix GPS


Back in the days when the iPhone 3GS held the title of “the best iPhone yet”, there came a little problem with Ultrasn0w unlockers: some firmware required an upgrade to iPad’s 06.15.00 baseband for the unlock to work. The reason behind this nuisance was the fact that the jailbreak gurus had managed to crash the iPad’s 3G baseband, while 3GS’ own 05.13.04 remained out of luck. While the unlock worked, it came with a rather hefty price of breaking push notifications and disabling GPS services. You just have to take a look at the number of apps that use GPS in their working to get an idea of the consequences of using iPad’s baseband on your iPhone 3Gs or 3G. Then, Ultrasn0w began supporting the 05.13.04 baseband, but there was no way to downgrade an iPhone 3GS or 3G from 06.15.00 to the former one. Now, thanks to redsn0w 0.9.14b1, users can downgrade the baseband on their jailbroken iPhone 3G/3GS to get working unlock, push notifications and GPS!

Downgrade 06.15.00 Baseband iPhone 3GS redsn0w 0.9.14b1

If you are one of those iPhone 3GS a or 3G users who have been on the iPad firmware for quite a while, you have waited long enough already, and hence, we will dive straight into the procedure for letting you downgrade your phone’s firmware to a more optimal version.


  1. Only iPhone 3GS and iPhone 3G should be unlocked using this procedure. It does not apply to any other iDevice model.
  2. All devices that have the serial number xx134— or above should not be used with redsn0w 0.9.14b1. This means that the third, fourth and fifth digits should form a number that is less than 134.


  1. If your iPhone meets the criteria cited above, download redsn0w 0.9.14b1 from the links provided at the end of this post.
  2. Find out the current iOS version running on your iPhone, and download its IPSW file by searching the web.
  3. Now, unzip the redsn0w file you downloaded in step 1.
  4. Run redsn0w.exe (under administrator mode in Windows).
  5. From the tool’s home screen, hit the Extras button.
  6. The next screen will present you with 7 more options, and you have to hit the Select IPSW button.
  7. Direct redsn0w to the IPSW file you downloaded in step 2.
  8. Follow the onscreen instructions to find out the exact version of your bootrom.
  9. Hit Jailbreak from the tool’s main screen.
  10. Once the IPSW file is jailbroken, a new set of options will come up. From among those options, select Downgrade from iPad baseband and Install Cydia, and hit the Next button.
  11. Put your iPhone in DFU mode (follow onscreen instructions if you don’t know how to do that). Now connect it to your PC or Mac, and hit the Next button.

The process may take a long time (according to the Dev-Team blog, it may be up to 8-10 minutes without any progress indicators, so make sure you don’t panic and disturb your device in any way). Once the device has successfully rebooted, simply unlock it using Ultrasn0w by heading to the Cydia store.

Download redsn0w 0.9.14b1 for Windows

Download redsn0w 0.9.14b1 for Mac OS X

  • gec

    When I run this procedure, baseband remained 06.15 and iccid stay unknown. Cannot find any carrier. 🙁 Can anybody help me?

    • veronique

      The same has happened to me — 3GS, old bootrom, 06.15.00 baseband and iOS 5.1. I have run all of the steps 4 or 5 times, ensuring the iPhone was fully off before going back to the jailbreak screen, getting RedSn0w to run through the pineapple process on my phone and even though it said it was done, my baseband is STILL 06.15.00 and my iPhone now does not recognize my SIM card nor get any signal. I have read many other posts of the same nature… I am going to try to re-install 06.15.00 baseband and at least get what I had before back… Anyone know what the deal is as to why we are not able to downgrade to bb 05.13.04???

      • none

        I had the same problem – solved by unlocking with 06.15.00 and then downgrading to 05.13.04

  • Xian Jin

    I have an iPhone 3GS updated to 5.1.1 with baseband 05.16.05. Can the same technique be used to downgrade the baseband to 05.13.04?