How to prepare for iOS 4.2 jailbreak with TinyUmbrella 4:21:01

TinyUmbrella developer has just released a new update for the application that allows you to manually save the certificates SHSH devices and that brings us to version 4.21.01. With this update the program now supports saving blob SHSH for the new 4.2.1 firmware and upgrade it to the baseband firmware preserving the previous iOS 4.1

Download links

• TinyUmbrella 4:21:01 (Windows)
• TinyUmbrella 4:21:01 (Mac)
• TinyUmbrella 4:21:01 (Linux)

Let's remember to always save your new certificate for any firmware that SHSH unlocked. It a very important part of ensuring the operation of the device to downgrade to a previous version of IOS.

How to prepare for iOS 4.2 jailbreak with Tinyumbrella

About a month ago I gave you guys a guide on how to use Limera1n to jailbreak your device on iOS 4.1. In that guide I mentioned a little program called TinyUmbrella.

With iOS 4.2 finally out, I’m fishing this program out again to give you guys a heads-up before you are thinking about jailbreaking your device.

In previous versions of iOS, you could use TinyUmbrella to block the baseband from updating. (This was key for people who needed an unlock to use their iPhones on another network.) Although this is still technically true, there’s a big issue with this now — Apple has made it so that a device will not start up if it notices that it’s not using the latest baseband for that model. So if you are relying on an unlock, this isn’t going to help you now.

I REPEAT: Don’t use TinyUmbrella to save your baseband. It’s not going to help you out with that.
What it will do, however, is save another critical piece of info as a back-up for you. TinyUmbrella does save the signature, or SHSH Blob, that Apple has for your specific handset. (This is what’s used to verify that your device is eligible for updating to a particular iOS version.) This is very, very useful if you update and then want to downgrade back to a previous version. After a period of time, Apple will stop providing these signatures, making it impossible to downgrade if you have not saved yours before.

Even if you don’t save your SHSH Blob, you will still be able to jailbreak. But again, you won’t be able to downgrade. So it’s basically a safety measure. You could try things, and then revert back if it doesn’t go well. This is why it’s strongly encouraged that people save their SHSH Blobs.

[UPDATE: It looks like a jailbreak has been issued for iOS 4.2.1. Check back to the site, and I'll have a tutorial posted soon! Just know this: If you depend on a carrier unlock, you have to be patient and STAY AWAY from this and iOS 4.2.1 until there's an official unlock released. For now, it's even more important to save your SHSH Blobs, so keep reading and be sure to prep your device before trying the jailbreak. Post to follow shortly.]

Here’s how you use TinyUmbrella (and no, you don’t need an already jailbroken device to do it):

1. Download TinyUmbrella
2. Connect your device to your computer and run Tinyumbrella
3. Make sure that in the “Advanced Options” that the request or loacation is set to Cydia.
4. Now select the iOS version that you want to save the SHSH blob for, which is currently iOS 4.1
5. Click the “Save My SHSH” button.
6. Now you are set.

Again, this is currently only to be used to save the SHSH Blob, in case you have any reason to downgrade your device in the future.

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We’re taking suggestions! Is there a feature or function you only wish you could have on your device? If there’s a jailbreak solution for it, we’ll find it. Just let us know what your biggest iOS wishes are in the comments.

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This article is presented for informational purposes only. Jailbreaking can void Apple’s iPhone/iPod Touch warranty. Any efforts or attempts at jailbreaking is done at the sole discretion of the user. Today’s iPhone assumes no liability or responsibility for any resulting user actions, software or hardware glitches or revocation of warranties. Proceed at your own risk.