iPhone, iPad, iPod Forums at iMore.com

[farbod21]

An SHSH blob or ECID SHSH is basically a unique signature which is checked against Apple servers whenever you decide to restore the firmware on any of your iDevices (iPhone, iPad and iPod touch). Once a new firmware is released, Apple stops signing the older firmware, hence making it impossible to restore back to the older firmware from iTunes. YOU MUST SAVE YOUR SHSH WHILE APPLE IS CURRENTLY SIGNING THEM.

Now to “why is it important to save your SHSH blobs”: The creator of Cydia has setup a new server which basically mimics Apple’s verification server and can save your older signature (SHSH blob) so that you can downgrade or restore back to the older firmware. This is important because if you don’t have your SHSH blob saved, and accidently update to new firmware, you’ll loose your jailbreak and furthermore, you wont be able to downgrade back to older firmware to re-jailbreak your device.

Now while Cydia can save your SHSH blobs on the server automatically by using the "Make my life easier" button, a utility has been released which allows for both saving blobs on the server and locally and also for restoring older firmware via iTunes. You can also use TinyUmbrella to save your SHSH without being Jailbroken and for the currently signed firmware even if your iDevice is using a lower firmware.
You can download it here: TinyUmbrella
Look for version you need on right hand column.

Instructions for saving your SHSH
1. Download and run TinyUmbrella and make sure your iDevice is detected.
2. Check "Advanced Options."
3. Under "Device / Version," select the firmware version you want to Save (You can only restore to versions that have SHSH saved).
4. Click on "Save my SHSH."
5. Repeat to save other firmware hashes if you wish.
6. Now, click on "Display SHSHs." It should listed all hashes you have saved on your computer for all your iDevices.

Instructions for restoring:
(Make sure you have saved your SHSH blob locally using method above. If not, repeat the method above for the firmware you wish to restore to.)
1. Backup iDevice in iTunes and then close iTunes.
2. Open TinyUmbrella and make sure you dont get any errors on startup or else you will need to make sure that port 80 is open and that your host file is not set to Read-Only.
2. Click on Start "TSS server,"
3. Download firmware you wish to restore to from here: iPhone/iPodTouch
4. Open Itunes and use the Shift/Option + Restore method to choose the firmware file you wish to restore to (Upgrade button cannot be used)
5. After your firmware is restored you might get a 1004 error. Not to worry, simply click "Kick Device out of Recovery" if you get it.
6. Restore Settings from Backup in iTunes and sync.

Done!

[TinyUmbrella]
[TinyUmbrella Readme]
[TinyUmbrella Dev on Twitter]
[Firmware Files]

[BrianT]

So what if you are on 4.1 and never saved SHSH files for 4.0.1? Can you download 4.0.1 and load that through Tiny Umbrella and JB 4.0.1?

[farbod21]

Originally Posted by BrianT

So what if you are on 4.1 and never saved SHSH files for 4.0.1? Can you download 4.0.1 and load that through Tiny Umbrella and JB 4.0.1?

No. Once Apple stops signing you wont be able to install that firmware unless you saved the SHSH. So lets say I saved 4.0.1, not 4.0.2, and saved 4.1. When 4.2 comes out, I can downgrade to either 4.0.1 or 4.1 but not 4.0.2 as I did not save it.

Its always a good idea to save your SHSH with TU whenever a new firmware is released and signed. You never know if you will need it and it takes 5 seconds of your time.

This can also be used to try new firmware or beta versions of firmware without worry of losing your JB for long periods of time.

As an added bonus, you can even use TU to upgrade your iPhone4 to iOS 4.1 and try it out without updating your baseband (rendering your unlock obsolete). You do this by using the restore method described above for 4.1 with the 4.1 SHSH blobs saved. (iPhone4 ONLY as the validation used by the device is different than previous models)

[UhanRodric]

I'm sure this has been covered already, just couldn't find an answer. To downgrade, do I need MY specific back-up/SHSH? Or for example, could you use someone else's file?

(Like the ones I used to Jailbreak/Unlock my 2G)

[Massie]

SHSH and .ipsw files are different things. What you used on your 2G sounds like a custom .ipsw. SHSH, which are unique to each phone, weren't used until the 3GS came out.

So—if you need SHSH, they do have to be yours.

[UhanRodric]

Originally Posted by Massie

SHSH and .ipsw files are different things. What you used on your 2G sounds like a custom .ipsw. SHSH, which are unique to each phone, weren't used until the 3GS came out.

So—if you need SHSH, they do have to be yours.

Thanks! haha. I've actually been wondering that forever now.

[larryganz]

I noticed tonight that the Cydia app has stopped reporting at the top of the screen which blobs it has saved on their server. It used to say SHSH blobs for iOS 4.01, 4.02 saved, or something like that, and now that is not displayed. Same thing for my iPad.

Is this a problem? When did this change?

[farbod21]

Originally Posted by larryganz

I noticed tonight that the Cydia app has stopped reporting at the top of the screen which blobs it has saved on their server. It used to say SHSH blobs for iOS 4.01, 4.02 saved, or something like that, and now that is not displayed. Same thing for my iPad.

Is this a problem? When did this change?

Cydia server has been swamped by all the traffic these past few days and so it has been returning time outs. Your SHSH's are saved, dont worry...

[steeletek]

PLEASE help!

My iPad is ALREADY JAILBROKEN. But on the Cydia page, I saw the prompt for "Make my life easier" but I accidentally hit the option: "I hate jailbreaking. Go away"!!!! Now the prompt is no longer there to save my SHSH!

I keep reading to use TinyUmbrella to locally save my SHSH. HOWEVER, can I still do this even though my iPad is already Jailbroken?!

[farbod21]

Originally Posted by steeletek

PLEASE help!

My iPad is ALREADY JAILBROKEN. But on the Cydia page, I saw the prompt for "Make my life easier" but I accidentally hit the option: "I hate jailbreaking. Go away"!!!! Now the prompt is no longer there to save my SHSH!

I keep reading to use TinyUmbrella to locally save my SHSH. HOWEVER, can I still do this even though my iPad is already Jailbroken?!

Yes, TinyUmbrella uses Cydia servers so you can save it that way as well. TinyUmbrella can be used if you jailbroken or not, makes no difference.