Note: This thread is out of date and has been superseded by the NEW FAQ sticky thread which can be found here - http://www.ipadforums.net/ipad-hacki...ed-2012-a.html. You are no longer able to respond to this thread. Please direct all your questions regarding blobs towards the new one. Thanks!
Welcome to the new and improved SHSH Blog Frequently Asked Questions Thread. Following lots of feedback, I have given it a bit of a re-write to make some of the questions and answers less technical and suitable for a wider audience. I hope you enjoy the new thread!
SHSH blobs can be a confusing subject for forum members who are new to the iPad. There is also a lot of misunderstanding and misinformation around the subject. This thread aims to be a one-stop-shop for SHSH related facts so we can demystify the subject once and for all…!
1. What are SHSH Blobs?Note: With the release of IOS5, saving SHSH Blobs for 5.x firmwares is currently a fruitless exercise. Apple has introduced additional security countermeasures in the blobs for IOS5 which mean they cannot be replayed at a later date, unlike those for 4.x or 3.x. The remainder of this FAQ is valid for 4.x and 3.x, but there is no guarantee that saving blobs for 5.x will be of any use to you in the future. However, development teams are working on the problem!
SHSH Blobs, or blobs for short, are digital signatures which Apple provides to you to authorise the installation of a particular version of IOS on your device. A set of blobs are like the key to allow iTunes to install a firmware file on your iPad.
2. Why are blobs so important?
iTunes will not let you install, update, or restore IOS on your iPad without valid blobs. There is no way to circumvent this security measure. So no blobs = no install. iTunes typical response in this situation is the dreaded message "This device isn't eligible for the requested build".
3. How are blobs generated?
Blobs are only ever generated by Apple on their own servers. They can't be created any other way. iTunes makes a request to the Apple signing server using your devices unique ID (ECID) plus the version details of IOS that you are trying to install and gets your unique SHSH Blobs back, but only if Apple decides that you are allowed to install that version of IOS on your device.
4. So what's the problem, you ask Apple for a blob and they provide it?
Apple will only provide you with blobs for the version of IOS which they decide is "current". At the time of writing, this is 4.3.5 for the iPad. You will not receive any blobs from Apple for older versions, such as 4.3.3. The period of time for which Apple will provide blobs for a version of IOS is referred to in the jailbreaking community as the firmware window.
So you may hear people say that the firmware window for 4.3.3 is now closed. This is because it is no longer possible to get blobs for 4.3.3 from Apple. Apple typically close the window on a particular version of IOS a few days after a newer version has been released.
5. Are blobs used on all devices?
Blobs are used on all modern Apple devices including the all iPads. They were introduced on the iPhone 3GS. Devices before this did not use them. It is safe to say that all new devices use SHSH Blobs, such as the iPhone4, AppleTV2G, and iPodTouch4G.
6. So I can only ever restore the "current" firmware?
NO! Here's the science bit. If you are smart and save your SHSH Blobs away, you can re-use them in the future once Apple has stopped providing them for that particular version of IOS. Apple won't give you blobs for 4.3.3 today, but if you saved the ones they gave you for 4.3.3 when you originally installed it, you can fool iTunes into using them because there is nothing in the current blob security which makes them expire. As long as you have them saved you can re-use them as much as you like. Genius!
7. I didn't save my blobs! Can't I just copy someone else's blobs and use those?
NO! - You didn't understand Q3. Blobs are unique to your device. They cannot be forged or spoofed, so you can't use someone else's, unless you also have their iPad!
8. How do I save my blobs?
There are 4 methods as follows:
TinyUmbrella (TU) - The Firmware Umbrella.
TU is a PC (both OSX & Windows) tool which saves your SHSH blobs locally on your hard disk. It is simple to use and puts you in control of your blob saving. You can download TU from - The Firmware Umbrella - TinyUmbrella
We have a very simple tutorial which you can follow to save all our current blobs and set yourself up for future blobs saving. Give it a go - HOW TO - Save your SHSH Blobs with TinyUmbrella
If you have a jailbroken device, Cydia will automatically save your SHSH Blobs on your behalf. Whenever you start Cydia you should see a line at the top of the home page with all your saved blobs (on Cydia servers) in green, similar to the following screenshot…...
This means that Cydia is storing blobs for me for all those IOS versions in green.
If you want to retrieve all of your SHSH Blobs from Cydia, use the tutorial for TinyUmbrella linked above. The tutorial will get all of your blobs from Cydia (if you have any) as well as the current blobs from Apple. Bonus!
This is a jailbreak application which you can install through Cydia on your iPad. Just like TU, it can retrieve blobs from either Cydia or direct from Apple, but this time it downloads the blobs onto your iPad. A nice feature is that is allows you to email the blobs anywhere you want (including to yourself!), which to be honest you MUST do since they are of little use to you on your iPad if you are going to restore it! . It is highly recommended for blob saving on the go, particularly if you are away from your PC, maybe on vacation, and hear that a firmware window is about to be closed!
Unlike the other options, iFaith does something really special, but please note iFaith only works on iPad1. It does not support the iPad2.. You should only use it as a lifeline to extract blobs as explained below, then use TU moving forward.
iFaith allows iPad1 owners to extract the SHSH Blobs for the firmware currently installed on your device. This is a real lifeline for iPad1 users who did not understand the importance of saving blobs, but perhaps still have 4.3.3 installed. Once the blobs are extracted from your device (which takes about 5 minutes to complete) iFaith sends the blobs to the iFaith servers for safe keeping. It also allows you to save them locally on your PC.
Additionally, you are able to build a pre-signed firmware for your device using the blobs you just extracted which can then be installed without the need to interact with the Apple signing servers. iFaith can be downloaded from - iH8sn0w.com
9. I have to be jailbroken to save my blobs, right?
NO! - Saving your blobs has nothing to do with whether your device is jailbroken or not. Just follow the tutorial on TinyUmbrella I posted above. It is never too soon to start saving your blobs!
10. I'm not really interested in jailbreaking, so I don't need to do this, right?
NO! - Saved blobs are useful for jailbreakers and non-jailbreakers alike. You never know when you might want to revert your device back to an earlier firmware. Who knows, there might be a feature which Apple adds or removes in the next version of IOS which you simply cannot live with / without. If you don't have blobs saved you can never downgrade to an earlier firmware. Just follow the tutorial linked above. It will take 15 minutes of your life! What are you waiting for!
11. I have SHSH blobs saved, how do I use them?
We have a great tutorial here which walks you though the process using TinyUmbrella - TUTORIAL - Restore your iPad using TinyUmbrella and SHSH Blobs
12. I still don't understand SHSH Blobs!
I have failed you grasshopper
Post your question in the thread or PM me and I will do my best to answer…