How to downgrade 06.15 baseband with Redsn0w 0.9.14b1

By : Mario Dabek posted on December 10, 2012
Version : 0.9.14b1
Firmware required : Yes

We just got an update from the Dev Team about a new release of Redsn0w.  I know, it’s been a while.

This version of Redsn0w, 0.9.14 beta 1 adds the ability to downgrade from the 06.15 iPad baseband that you might have applied to unlock your iPhone.

Many of the iPhone 3G & 3GS users have applied the 06.15 iPad baseband update to their iPhones. Why ? At the time iOS 4.2.1 was introduced, ultrasn0w (software unlock package) didn’t have the compatibility at that time to unlock the iPhone baseband. However developers figured out that you could in fact load the iPad 06.15 baseband that was bundled with the iPad iOS 3.2.2 and dump it to your iPhone. Since ultrasn0w had the compatibility with the 06.15 baseband, applying this hack to your iPhone, allowed users to unlock their iPhone using ultrasn0w on 4.2.1 with iPad 3.2.2 baseband (06.15) i know kinda confusing.

Although applying such an update to your iPhone was beneficial (free unlock), it had some downsides. The iPhone could no longer be restored or updated using iTunes, because of the mismatch of the baseband & iOS firmware. This means anytime you wanted to upgrade, you would have to build a custom ISPW and apply it using one of the jailbreak tools, not fun. Another key thing that most users had a problem with is the loss of signal on any GPS apps. This again was because the users were using the wrong baseband (modem firmware) Developers of this hack also said that downgrading from his firmware was next to impossible, so users had to make that ultimate decision, get the unlock and deal with shitty updates, or no unlock and regular updates.

However today things have changed a bit. Today developers have released Redsn0w 0.9.14B1. And this software finally allows users to get back to Apple’s 05.13.04 baseband, and restore the ability to use your GPS and iTunes to update your device once again.

Lets have a look at the detailed instructions from the Dev Team’s Musclenerd

The folks who unlocked with ultrasn0w and updated their iPhone baseband past 05.13.04 will “typically” have the 06.15 baseband, according to MuscleNerd. Still, in case the client never had 05.13.04 on their device before, redsn0w now makes it likely to downgrade particularly from 06.15 to 05.13.04.

few 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!

Let us know your experience with this below.

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.