How to downgrade your iPhone 3GS from 06.15 iPad Baseband

By : Mario Dabek posted on June 18, 2012
Blackra1n
Version :
Firmware required : Yes

Update 1 : Tip: many people who saw “No signal” issues after the downgrade from 06.15 fixed it by re-installing Mobile Substrate and/or ultrasn0w

Musclenerd has just release a new version of redsn0w, this time with support for downgrading your iPhone 3GS from the 06.15 iPad baseband.
Only use this if you updated your iPhone 3GS to the iPad 06.15 baseband !!!

Many of the 3GS owners in the jailbreak community have updated their baseband to 06.15 which is actually the baseband from the Apple iPad. This allowed users to unlock their iPhone’s using the software unlock and thus allow users to use different carriers on their 3GS headset. However as good as this was, this also made your 3GS stuck on that firmware. When users updated to the 06.15 baseband this actually cut off any possibility to future iOS updates. Until today ! Musclenerd has figured out and release the new version of Redsn0w for just this reason. People are finally able to take th 06.15 baseband on and update to the latest iOS firmware, including iOS 6.

More details below, read carefully.

The iPhone Dev Team is happy to announce a baseband downgrade option in redsn0w for those who are using the iPad’s 06.15 baseband on the iPhone3G or iPhone3GS.

Typically you’d have the 06.15 baseband if you unlock with ultrasn0w but updated your iPhone baseband past 05.13.04.  With this new capability, you can now downgrade specifically from 06.15 to 05.13.04 (even if you never had 05.13.04 on that device before).  This gives you the best of both worlds: ultrasn0w compatibility and a normal iPhone baseband with full GPS and the ability to use stock IPSWs again.

Here are the steps:

  1. Use the “Extras->Select IPSW” button in redsn0w to tell it which firmware version you have installed (new-bootrom 3GS users can usually skip this step but it doesn’t hurt for them to do it too).
  2. Do a controlled shutdown of your iPhone (“slide to power off”).  This step is very important to avoid mount problems when the ramdisk is running!
  3. Go back to the first screen and click “Jailbreak”.  Enable the “Downgrade from iPad baseband” checkbox, disable Cydia if you already have it installed, and click Next to proceed through the normal DFU ramdisk steps.

After the ramdisk gets launched and you see the Pwnapple running on your iPhone, you’ll eventually get to the “Flashing Baseband” step.  THIS STEP TAKES A VERY LONG TIME to complete and there won’t be any feedback while its running.  Please just let it be for the next 3-8 minutes!  When the ramdisk has done its job it will reboot the phone on its own.

For those who are wondering if you can update your 3G or 3GS to 06.15 solely for the purposes of downgrading to 05.13.04, the answer is “yes” for 3G owners, and “maybe” for 3GS owners.  The iPad baseband is not compatible with 3GS units manufactured week 34 of 2011 or later.  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!

Thanks very much to @dilbert4life for graciously loaning us his 3GS at 06.15 (we had no such devices because we always prevent BB updates!)

If you have any questions or comments, please use our comments section below!

Here are the download links.  Enjoy!

 

About this Author
Mario Dabek
Mario Dabek is a technology journalist residing in Ontario, Canada. Covering everything from the latest Apple & Jailbreak news, to writing step by step jailbreak tutorials. Some key contributions include the world famous "Jailbreak Chart" as well as the "100 Reasons to Jailbreak" Video.