Jailbreak iOS 4.2.1 Untethered On iPhone 4 Without Updating Baseband Via TinyUmbrella [Guide]

It’s been a busy day for jailbreakers since Chronic Dev-Team has released greenpois0n RC5 which jailbreaks your iPhone 4/3GS, iPod touch or iPad on iOS 4.2.1 completely untethered and we recently published a step-by-step guide on how to do it. However, that is only suitable for those who do not rely on a software unlock (ultrasn0w) for using their iPhone on an unsupported carrier. Now until a pwnage tool comes out for this, folks at FSM have posted a nice and quick guide for iPhone 4 users to jailbreak on iOS 4.2.1without updating their baseband and preserving ultrasn0w unlock.

Before you proceed, please note:

  • This procedure is for iPhone 4 ONLY!
  • Make sure your iPhone 4’s current baseband (e.g 1.59.00) is supported by ultrasn0w 1.2. (you can check the list of supported basebands here)

Step 1:

Download and install TinyUmbrella from here .

Step 2:

Download the official iOS 4.2.1 firmware for iPhone 4 here.

Step 3:

Load TinyUmbrella and Start TSS Server. To make sure it’s running, check out the logs…

Jailbreak iOS 4.2.1 Untethered On iPhone 4 Without Updating Baseband Via TinyUmbrella [Guide]

Step 4:

Start iTunes

Step 5:

Now Plug-in your iPhone 4.

Step 6:

Restore to official iOS 4.2.1 using the downloaded firmware

Step 7:

You will get an Error 1013. That’s totally normal.

Step 8:

Put your iPhone 4 in DFU mode and jailbreak it untethered using greenpois0n RC5 by following this step-by-step guide.

Enjoy!

IMPORTANT:

  • Fixing issues with greenpois0n RC5 Untethered Jailbreak for iOS 4.2.1.
  • How To Unlock iOS 4.2.1 On iPhone 3GS / 3G With Baseband Update To 06.15.00 Using PwnageTool 4.1.3 + Ultrasn0w 1.2 [Guide]

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About the Author

I'm a technology enthusiast specializing in Diagnostic Radiology. I'm crazy about Formula 1, all sorts of gadgets, surfing, console gaming, movies, music & I simply LOVE high-end designer wear! Follow me on Twitter @DrUsmanQ

4 comments

  1. Downloaded and installed TinyUmbrella and followed the directions up to the point where it says, “Restore to official iOS 4.2.1 using the downloaded firmware.” How do I restore to the downloaded firmware, rather than the one iTunes tried to download when I click on the “restore” button in iTunes? Also, assuming I can restore to the downloaded firmware, how do I put my device into DFU mode?

    Thanks!

  2. Downloaded and installed TinyUmbrella and followed the directions up to the point where it says, “Restore to official iOS 4.2.1 using the downloaded firmware.” How do I restore to the downloaded firmware, rather than the one iTunes tried to download when I click on the “restore” button in iTunes? Also, assuming I can restore to the downloaded firmware, how do I put my device into DFU mode?

    Thanks!

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