iPhone Why can't you downgrade without saved SHSH?

DoNoHarm

macrumors 65816
Original poster
Oct 8, 2008
1,120
12
Maine
Hey everyone, I recently purchased a 4S and have been pretty bummed that I can't downgrade the iOS without having saved SHSH files... When I try to search on this forum for ways to downgrade without the SHSH files, I just find a bunch of "it's not possible" like posts, which aren't really helpful.

Could someone give a better explanation as to why the jailbreaking community hasn't been able to facilitate this? Thanks.

Edit: I'd even be down with a tethered downgrade, is this possible?
 
Last edited:

Applejuiced

macrumors Westmere
Apr 16, 2008
40,650
6,403
At the iPhone hacks section.
Why do you need someone to give you a better explanation?
Easy answer it cannot be done.
More complicated answer: Search and educate yourself further on what shsh blobs and apt tickets are. What they do and how they are used to validate a restore of an idevice.
But from the looks of it its not something that you want to hear or believe thus you will just keep wasting your time looking at fake and made up youtube videos and websites that claim you can do it by magically jumping through 200 hoops and it will somehow never work for you to downgrade.

Here's some useful info below:
http://en.wikipedia.org/wiki/SHSH_blob
http://www.idownloadblog.com/2011/03/13/what-is-an-shsh-blob/
https://theiphonewiki.com/wiki/SHSH
http://www.saurik.com/id/12
 

eyoungren

macrumors Core
Aug 31, 2011
21,178
13,010
ten-zero-eleven-zero-zero by zero-two
Hey everyone, I recently purchased a 4S and have been pretty bummed that I can't downgrade the iOS without having saved SHSH files... When I try to search on this forum for ways to downgrade without the SHSH files, I just find a bunch of "it's not possible" like posts, which aren't really helpful.

Could someone give a better explanation as to why the jailbreaking community hasn't been able to facilitate this? Thanks.

Edit: I'd even be down with a tethered downgrade, is this possible?
Well…basically it's this way…

The last time SHSH mattered it was with iOS 5 and below. Blobs are part of the authentication of your iOS. Without them and more specifically without YOUR personal blobs you can't authenticate yourself to downgrade.

Apple changed things a bit in iOS 6. Saurik missed it and many, many people ended up with useless/incomplete blobs.

Apple changed things again in iOS 7. Guess what? No blobs for authentication with iOS 7. So, even if you somehow managed to have a complete set of iOS 7 blobs they would STILL be useless to you because Apple no longer uses blobs for authentication.

So…there's why.
 

dhlizard

macrumors G4
Mar 16, 2009
10,213
118
The Jailbreak Community
Simple answer...

Apple's servers authenticate the attempted install of firmware to each device, every time.
In the "good old days" it was possible to "trick" iTunes (using deficiencies in the devices) into authenticating the firmware using saved, complete SHSH files.

Apple eventually got tired of us restoring to unsigned firmware, eliminated the weakness in newer devices and changed the method of authentication in newer firmware.

So, it cannot be done with newer devices on newer firmware (which includes your 4S).

If you wish to learn all about SHSH Google "Caching Apple's Signature Server"
 

glsillygili

macrumors 6502
Dec 16, 2011
311
0
New York
Simple answer...

Apple's servers authenticate the attempted install of firmware to each device, every time.
In the "good old days" it was possible to "trick" iTunes (using deficiencies in the devices) into authenticating the firmware using saved, complete SHSH files.

Apple eventually got tired of us restoring to unsigned firmware, eliminated the weakness in newer devices and changed the method of authentication in newer firmware.

So, it cannot be done with newer devices on newer firmware (which includes your 4S).

If you wish to learn all about SHSH Google "Caching Apple's Signature Server"
And in the really good old days you didn't even need SHSH blobs, just the IPSW :mad:
 

Totally

macrumors 6502a
Feb 22, 2012
742
258
West Coast = Best Coast
You know, if you did a simple google search you would have found out that blobs only work for the iPhone 4 and that there is no way to downgrade a device that is a 4s or higher.

There is no way - what question could you have? It can't be done by any means.
 

DoNoHarm

macrumors 65816
Original poster
Oct 8, 2008
1,120
12
Maine
whoa... I really appreciate the helpful replies, but some people posting seem to have serious angst about a simple question. Take it easy people, it's just a simple question. Isn't getting this worked up about it kind of self defeating?
 

TriJetHero

macrumors 601
Oct 13, 2010
4,950
137
World
whoa... I really appreciate the helpful replies, but some people posting seem to have serious angst about a simple question. Take it easy people, it's just a simple question. Isn't getting this worked up about it kind of self defeating?
As a 65816 you are not a newbie on this forum, you should know better than your post suggests.....