The Dev Team released the redsn0w 0.9.6 b4 today and with that, you could jailbreak 4.2.1 iOS on your iPhone, iPod Touch or iPad. But it supports only tethered jailbreak on some of the devices which are given below. Till an unlock for the iOS 4.2.1 is released, you should not update to iOS 4.2.1 as it will upgrade the baseband.

Jailbreak iOS 4.2.1

Tethered jailbreak :

  • iPhone New Bootrom
  • iPhone 4
  • iPod Touch 2G (MC Model)
  • iPod Touch 3G
  • iPod Touch 4G
  • iPad

Untethered jailbreak :

  • iPhone 3G
  • iPhone 3GS (Old Bootrom)
  • iPod Touch 2G (Non MC Model)

Now if you want to jailbreak iOS 4.2.1 on Windows or Mac OS X, then here are the steps to do it.

1. Download iOS 4.2.1 from here.

2. Update your iPhone, iPod Touch or iPad to iOS 4.2.1.

3. Download Redsn0w 0.9.6 b4 from here.

4. Launch Redsn0w 0.9.6 b4 and browse to the iOS 4.2.1 firmware.

Jailbreak iOS 4.2.1

5. Now click ” Next ” after Redsn0w verifies the IPSW. Now Redsn0w prepares the jailbreak data.

Jailbreak iOS 4.2.1

6. In the next window, select ” Install Cydia ” option. You could also select any other option also. Then move forward.

7. Now switch off your device but keep plugged in to the computer and click ” Next “.

Jailbreak iOS 4.2.1

8. Now go into recovery mode by pressing the power and buttons for 10 seconds and then release the power button, but keep holding the home button until the iOS 4.2.1 jailbreak process begins.

9. Wait till Redsn0w finish the iOS 4.2.1 jailbreak process.

NOTE : For the devices mentioned above under tethered jailbreak category, if you want to SSH into your device, you need to use the ” Just boot tethered right now ” in Redsn0w before doing it.

Jailbreak iOS 4.2.1

Stay Tuned to Tips Needed for more Updates!