Jailbreak iOS 4.2.1 Untethered using Redsn0w (Redsnow) 0.9.7b3

iPhone Dev Team has once again updated their redsn0w 0.9.7b3 application to jailbreak iOS 4.2.1 untethered on iPhone 4, iPod Touch 4G and iPad. It is a backup plan and does its job but has its own limitations.

• Do not use this if you need ultrasn0w. Things may get wrong and you may not be able to unlock your device.
• You need to have iOS 4.2b3 ipsw file and its SHSH blobs saved on Cydia. Currently, locally saved blobs will not work.
• Only for Mac OS
• You need to have usbmuxd software installed on your Mac. Download it here.
• Bluetooth does not work as of now.

Below are the step by step guide to jailbreak iOS 4.2.1 untethered on iPhone 4, iPod Touch 4G and iPad:

1. Using redsn0w 0.9.6b4, jailbreak your iDevice tethered first using instructions posted here.
2. Make sure you have 4.2b3 SHSH blobs saved on cydia.
3. Install usbmuxd on Mac and execute the following commands:

chmod +x tcprelay.py

./tcprelay.py -t 22:2222

4. Download redsn0w from here. Start redsn0w 0.9.7b3 and point it to 4.2.1 firmware.
5. Click next and select “Jailbreak Monte”. Select 4.2b3 ipsw on the following screen.
6. Follow the onscreen instructions to put your device in DFU mode.
7. Now sit back and relax. After some time, you’ll have fully jailbroken iDevice running 4.2.1 untethered.

Enjoy