How to Jailbreak IOS 4.2.1 Untethered with Redsn0w (MAC)

The iPhone Dev-Team have just released their “backup plan” (Redsn0w 0.9.7) for untethered iOS 4.2.1 jailbreak. The just released beta version of Redsn0w will enable you to jailbreak (untethered) iPhone 4, iPad and iPod touch 4G on iOS 4.2.1.

Here’s what you will need to know before proceeding:
iPhone, iPad or iPod touch running iOS 4.2.1
iPhone, iPad or iPod touch with SHSH blobs saved for iOS 4.2 Beta 3.
Mac OS X
Access to iOS 4.2 Beta 3 firmware file.
If you rely on Ultrasn0w unlock, STAY AWAY from this version of Redsn0w.
Currently limited to iPhone 4, iPad and iPod touch 4G only.

The best thing about this “backup plan” is that it doesn’t require you to restore or re-jailbreak your iPhone, iPad or iPod touch.

Warning Note:

This is a beta tester program. Things can go very wrong, so please don’t even consider testing if you have pictures or other media on your device that you haven’t backed up!

Until we fix some sandbox issues with bluetooth, the bluetooth functionality is disabled.

Here’s how to do it:

Note: Skip to Step 2 if you have previously jailbroken (tethered) your iOS device on iOS 4.2.1 with Redsn0w.

Step 1: Restore your iOS device to the official iOS 4.2.1 firmware and jailbreak it using Redsn0w by following our step by step guide posted here.

Step 2: This untethered jailbreak completely relies on SHSH blobs saved for 4.2b3 (iOS 4.2 Beta 3). To check whether you have SHSH blobs saved for iOS 4.2 Beta 3, start Cydia and wait for it to completely load the main page. You should now see “SHSH: 4.2b3” on top as shown in the screenshot below:

Step 3: Download Redsn0w 0.9.7 and connect your iPhone, iPad or iPod touch with Mac.

Step 4: Now download usbmuxd from here and extract it on your computer. Start Terminal in python-client directory and then run the following commands as shown in the screenshot below.

chmod +x tcprelay.py

./tcprelay.py -t 22:2222


Step 5: Start Redsn0w and point it to the official iOS 4.2.1 firmware file.


Step 6: Now click “Next” and select “Jailbreak Monte” option, followed by selecting iOS 4.2 Beta 3 firmware file.


Step 7: Now make sure your device is both OFF and PLUGGED IN to the computer before you click “Next”.

At this stage you will be presented with a screen where you will have to quickly hold “Power” button and then while holding the “Power” button, you will now have to hold “Home” button too. Now after few seconds release “Power” button but keep holding “Home” button until installation begins.


Step 8: Sit back and enjoy while Redsn0w will do all the rest for you. Once done, your iPhone, iPad or iPod touch will restart automatically and you will find it fully jailbroken (untethered) on the latest iOS 4.2.1 firmware.

Download Here