Jailbreak iOS 4.2.1 iPhone 4/3GS/3G, iPod touch, iPad With Redsn0w 0.9.6B2

Apple has just released iOS 4.2.1 GM (Gold Master) build for developers for iPhone and iPod Touch. Good news is iOS 4.2.1 GM for iPhone, iPod Touch, and iPad (build 8C148) can be jailbreaked using Redsn0w 0.9.6B2.

You can jailbreak your iPhone 3G, iPhone 3GS, iPhone 4, iPod Touch 2G, iPod Touch 3G, iPod Touch 4G and iPad running on iOS 4.2 using Redsn0w 0.9.6b2.

If you are jailbreak app developer and looking for way to jailbreak iOS 4.2.1 then here is easy guide to do it.

Please note,

• if you rely on Ultrasn0w to unlock your iPhone then you should stay away from this guide as updating to iOS 4.2.1 will update your baseband for which there is not unlock available yet.
• Don’t install Cydia because it’s not compatible with iOS 4.2, if you are not a developer than stay away.

Follow these instruction to jailbreak iOS 4.2.1 GM. First you required these file

• Redsn0w 0.9.6B2
• Download iOS 4.1
• Download iOS 4.2.1

How to Jailbreak iPhone 4, 3GS, & 3G & iPod Touch 4G, 3G, & 2G running iOS 4.2.1 using RedSn0w 0.9.6b2

1. Update iPhone,  iPod touch to iOS 4.2.1 GM (Proceed only if you know what you doing, we will not be responsible if your iPhone gets locked)

2. Now launch Redsn0w 0.9.6B2, click on browse and select firmware iOS 4.1 ipsw (not iOS 4.2.1 GM) for iPhone.

3. Click Next and Redsn0w 0.9.6 B2 will prepare data for jailbreak.

4. Now select “Install Cydia” and click Next. You can also select some other tweaks and options If you want.

5. Than you will need to put your iPhone in DFU mode, just follow the on-screen instructions to set your iPhone in DFU mode.

6. Redsn0w will patch and install some files to your iDevice, wait until Redsn0w completes the rest of the process.

Once it is done, your iPhone will restart automatically. Now enjoy your jailbroken iPhone with iOS 4.2.1 GM Build.

The current version of Cydia is not compatible with iOS 4.2.1 GM build and it may crash, you may need to wait for the release of the patched version of Cydia for iOS 4.2.1 GM build.