How To Upgrade To iOS 4.3.1 While Preserving Baseband And Jailbreak : Step By Step Tutorial ~ Blog O'Nerd

One more iOS update from Apple. The latest iOS 4.3.1 update was released by Apple just a few days ago. And after 4.3.1 update it was time for a Jailbreak yeah? So the iPhone Dev Team released PwnageTool and redsn0w, the untethered jailbreak tools for all Apple iDevices except iPad 2. The latest redsn0w jailbreak contains exploit found by i0n1c as I mentioned in a post some days ago. After iPhone Dev Team's PwnageTool and redsn0w, it was iH8sn0w who released sn0wbreeze 2.5. Both the PwnageTool and sn0wbreeze allows you to prevent baseband of your device while upgrading your device to latest firmware. In this tutorial, I am going to show how to upgrade to iOS 4.3.1 while preserving your current baseband and Jailbreak successfully. Lets start then.

What this process will do?
After successful completion, you will get your device upgraded to iOS 4.3.1. Your current baseband will not be upgraded and after that, you will get your device jailbroken.

Before beginning, please note that there is no unlock available for devices on iOS 4.3.1 even with preserved, unlockable baseband. The iPhone dev Team is working on ultrasn0w to get it working on iOS 4.3.1 but there are no news yet. So if you are not on official SIM and want to unlcok your device, then please don't upgrade to iOS 4.3.1 and wait until latest unlock is made available. Once unlock is available, you can jailbreak and unlock.

Update : ultrasn0w has been updated to work with preserved baseband on iOS 4.3.1. So if you upgrade iOS but preserve the unlockable baseband, then you can use ultrasn0w to unlock your device. DO NOT upgrade to stock 4.3.1 or else, you will loose your chance to unlock your device. Use custom IPSW only as mentioned in this tutorial.

Things you need.

iDevice on iOS less that 4.3. (No iPad 2)
"Appropriate" iOS 4.3.1 IPSW file for your device. (Links at the end)
sn0wbreeze 2.5 (or 2.5.1 which will be released soon)
redsn0w 0.9.6rc9
iTunes 10.2 or later.
Windows PC or Mac.

Things used in this tutorial.

iPhone 3GS new bootrom on iOS 4.2.1 with baseband 5.13.4
iTunes 10.2.1.1
Windows 7
Good music playing in the background.

After you get everything ready follow steps described below.

You have two choices to jailbreak your device on iOS 4.3.1. Either use sn0wbreeze or redsn0w.

Method 1
If you want to use sn0wbreeze to jailbreak, please follow this tutorial : How To Create Custom IPSW, Jailbreak, Activate and Unlock Your iPhone On iOS 4.2.1. A Step by Step Guide

If you use sn0wbreeze to jailbreak your device, then no need to follow any other steps given below.

Method 2
If you want to use redsn0w to jailbreak your device, then follow the steps given below.

Step 1 : Upgrading to iOS 4.3.1 while preserving current baseband.
Follow this tutorial : How To Preserve iPhone Baseband In Windows Using sn0wbreeze 2.2 While Upgrading To iOS 4.2.1. Yes the version of both sn0wbreeze and iOS are different but the steps are same 100 percent. No difference at all. After custom IPSW is created and sn0wbreeze says Done, close sn0wbreeze and follow the next step to get in Pwned DFU

Step 2 : Get your device in Pwned DFU mode.
Now we need to get the device in Pwned DFU mode so we can use the custom IPSW created with sn0wbreeze and upgrade the device to iOS 4.3.1. So after creating custom IPSW for your device, follow this tutorial : How To Enter Pwned DFU Mode And Use Custom IPSW Firmware.
You can either get in Pwned DFU mode using redsn0w or iREB. Your choice. The version for redsn0w used in this tutorial is different but the method again, is same.
Step 3 : Jailbreaking iOS 4.3.1 with redsn0w.
After upgrading your device to iOS 4.3.1, now we need to jailbreak it. We will use redsn0w 0.9.6rc9 to jailbreak.

Step 3.1
Run redsn0w and select the IPSW file you downloaded from Apple. If you have iPhone 3GS, then it will ask if you have older or newer model of iPhone 3GS. Select Yes if you have newer model or No if you have older model.

Don't pay attention to the redsn0w version shown on the screenshots. The version is older. I have limited space on picture host so I have to use older images.

Click Next.

Step 3.2
On the next screen select the Install Cydia box if not already done.
Click Next.
Now redsn0w will prepare data needed for jailbreak.

Step 3.3
The next screen asks you to have your device switched off and connected to your computer. Do so if not already done and click Next.

Now follow the steps shown on redsn0w. Once your device is in DFU, redsn0w will start jailbreak process and your device will be jailbroken within a minute.

Now you have your iDevice on iOS 4.3.1, you have preserved your baseband and have successfully jailbreak your device.

Download Links

Download iOS 4.3.1 (stock) IPSW.