November 24, 2010 by James
Now that the iOS 4.2.1 is available to download for the iPhone, iPad and iPod Touch, while the iPhone Dev Team have released redsn0w 0.9.6b4 jailbreak tool for it, those who are new to jailbreaking may be wondering how the process is done.
Below you will find a full how to guide that will explain step by step how to jalbreak iOS 4.2.1 on your idevice using redsn0w 0.9.6b4.
PLEASE KEEP IN MIND THAT ACCORDING TO THE IPHONE-DEV TEAM IF YOU WANT TO BE ABLE TO UNLOCK YOUR IPHONE YOU SHOULD STAY AWAY FROM IOS 4.2.1. SO IF YOU INTEND ON UNLOCKING YOUR IPHONE IN THE FUTURE DO NOT UPGRADE TO IOS 4.2.1 AND DISREGARD THIS ENTIRE TUTORIAL.
Before we begin you might want to take SHSH blobs of your currently installed iOS version using TinyUmbrella before you do anything. Just in case.
IOS 4.2.1 JAILBREAK GUIDE
* PLEASE UPGRADE TO iTunes 10.1 FOR BEST RESULTS
* WINDOWS 7 USERS SHOULD RUN redsn0w IN “XP COMPATIBILITY” MODE
#1 – Download redsn0w 0.9.6b4.
#2 - Download the corresponding iOS 4.2.1 firmware for your exact iPhone model to your computer (right click on it and select to save).
#3 – After connecting your iPhone to your computer, open iTunes, hold down your keyboard’s SHIFT button and click on “upgrade”.
#4 – Select the iPSW iOS firmware file that you’ve just downloaded in step #2 and let iTunes upgrade your iOS to iOS 4.2.1.
#5 – Start redsn0w 0.9.6b4.
#6 – Inside redsn0w, select the same IPSW file that you’ve just downloaded and used in step #4.
#7 – Select whatever options you want (hint: you’ll probably want to select to install Cydia) and click on “next”.
#8 – Make sure your iPhone is connected to your computer and is turned off. Then click on “next” again.
#9 – Following the instructions on your screen, enter your iPhone into DFU mode (by holding down the power and home button for about 15 seconds and then releasing the power button while still holding down the home button)
#10 – Now the jailbreak process will begin and it will take a few minutes for it to complete.
If everything worked okay, your idevice was successfully jailbreaked.
And directly below you can see a video tutorial of the process.
Keep in mind that with the newer iPhone 3GS and iPhone 4 devices, as well as with the iPad and iTouch you will only have tethered jailbreak. That means that if you want to use Cydia or access non-AppStore apps you’ll need to do a “tethered boot” first. That can be done by selecting the option “Just boot tethered right now” from redsn0w. You’ll need to do it every time you reboot your device.
- Download: redsn0w 0.9.6b4 to jailbreak iOS 4.2.1 on iPhone, iPad, iTouch
- Download: redsn0w 0.9.6b5 iPhone / iPad / iTouch iOS 4.2.1 jailbreak [Mac / Windows]
- Ultrasn0w iOS 4.2.1 iPhone unlock coming this week + untethered redsn0w iOS 4.2.1 jailbreak soon!
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