How to downgrade baseband 6.15.00 on iPhone 3G 3GS

The iPad baseband 06.15.00 was a dark shadow on iPhone 3/ 3GS users for a long time. However, MuscleNerd pushed out a redsn0w update to allow affected users to downgrade from 06.15.00 baseband to a lower 05.13.04 baseband.

How to downgrade baseband 6.15.00 on iPhone 3G 3GS

How to downgrade baseband 6.15.00 on iPhone 3G 3GS

For those who are reading this for the first time, downgrading to a lower baseband will allow iPhone 3GS/ 3G users to unlock their device with ultrasn0w 1.2.7. It will also enable the device’s GPS capabilities. Before you begin, read this warning from the iPhone Dev Team: If you have an iPhone3GS and if digits 3-5 of its Serial Number are 134 or later (xx134…), then you should NOT try to install the 06.15 baseband on your 3GS!  It will brick your radio, preventing both the downgrade from working and normal iPhone software from using it as a phone!  Be warned! Pre-requisites

  • Backup all the important data on your phone.
  • The battery should be charged at least 80%.
  • This tutorial is meant only for iPhone 3/3GS with baseband 06.15.00.

Downgrade baseband 06.15.00 to 05.13.04 baseband: 

Step 1: Download the latest version of redsn0w for Windows or Mac.
Step 2: Extract the file on the desktop of your Windows or Mac.



Step 3: Download the current iOS IPSW file you are having on your iPhone. (Download here). If you’re not sure about the iOS version, go to Settings > General > About Version. Save the downloaded file where you can easily access it.  

Step 4: Open Redsn0w and tap on the Extras button on the screen.  

Step 5: Next, tap of the Select IPSW option. Point the redsn0w tool towards the IPSW file downloaded in Step 3. Now tap on Open when you’ve located the required IPSW.

Step 6: Redsn0w will now ask whether there’s an iPhone 3GS with an old bootrom or a new one, and the instructions should be read carefully from here to prevent any damage to the device.  

Step 7: Head back to the main screen and tap on the Jailbreak option. After a while, there will be some different options presented to you.  

Step 8: Tap the Downgrade from iPad baseband and Install Cydia option and tap Next. Uncheck Install Cydia option if you’re already jailbroken.



Step 9: The device should be powered off and unplugged. Now put the device in DFU mode. To do so, press and hold the Power button for 3 seconds, and without releasing the Power button, press the Home button and keep both of them pressed for 10 seconds more. Now release the Power button, and keep the Home button pressed for 10 more seconds. You should be in DFU mode now.  

Step 10: While in DFU mode, Redsn0w will begin the downgrade process. Don’t do anything and be patient. If you followed all of the above steps correctly, the device will reboot and there will be a new baseband 05.13.04 on it. Now your iPhone 3G/3Gs can be unlocked using ultrasn0w from cydia.

Click Here To Get Your iPhone Unlocked Now – For Most Worldwide Networks

  1. Anonymous says:

    Followed steps and got the new baseband but still no GPS?

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