When you buy a new iPod Touch, iPhone, iPad, Apple TV 2, it already comes preloaded with firmware. Let’s say someone purchases a new iPhone 4. It comes with 4.1. The user is indeed able to jailbreak it by a series of jailbreaking tools available these days. However, lets say that the user has a conflict with the device during the usage on the firmware that came preloaded. They would most likely want to start fresh and do a restore.
But wait, if Apple isn’t signing 4.1, how are you going to grab these blobs? Well, believe it or not, but the blobs are actually still on the device for that firmware. This is because the boot chain relies on these blobs. Its basically another signature check of Apple but is given to the device originally from Apple via a Restore/Update.
So, what if we can extract these blobs? Well we can!
Over the last month, I’ve been caught up with finals, but that is all over and done. So, development on this new tool has been working non stop! I’m going to explain again on what this exactly does.
If you have a device that is on a firmware that Apple is not signing (example: 4.1), and you wish to grab blobs for, you can with the new upcoming tool. Just ensure that you don’t press that Update/Restore button in iTunes. Everytime you restore or update, these blobs get replaced by completely new blobs for the firmware you are updating/restoring to.
There is a free tweak that just got pushed out called “RecoveryGuard” by pushfix.
You can grab this off his repo — "http://cydia.pushfix.info" (I highly suggest you install this for anyone that you think is going to accidentally press that button in the future while waiting for this tool to arrive.
Also, PLEASE ensure that you grab all future shsh blobs by using semaphore’s (notcom) TinyUmbrella Utility available OVER HERE!"