[What are SHSH Blobs ] [How to save SHSH blobs] [How to Downgrade FW using SHSH] [Fix 3194 Errors]
First Of All:
What exactly is SHSH blob or ECID SHSH? Well, it is basically is a unique signature which is checked against Apple servers whenever you decide to restore the firmware on any of your iDevice (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.
Now to “why is it important to save SHSH blob”: 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.
This is a tutorial on how to downgrade to an earlier firmware on your iDevice using SHSH files you have previously saved for that firmware revision.
This tutorial is for PC/Mac users ,
Step 1: Download the appropriate firmware files for your iDevice from here. Also download Latest TinyUmbrella from here (used to bypass Apple's authentication servers and to kick your device out of recovery mode)
Step 2: Put your iDevice into DFU mode (the video below will walk you through how to do this):
Note: Your iPhone screen should be blank (black in color), if it is not, or if the Connect to iTunes screen comes up instead then you are most likely in Recovery Mode, not DFU mode. Please re-watch the video to ensure your device is in DFU mode.
Step 3: This step(and steps 4 and 5) are applicable to iPhone 4, iPhone 3GS, iPod touch 4G, iPod Touch 3G and iPod touch 2G (MC model) which have their SHSH files saved for the firmware you downgrading to. If you don’t have your SHSH files saved, you cannot downgrade the mentioned devices. We must trick iTunes into thinking it's validating the firmware file you downloaded from the Apple servers when in reality it will be verifying from your locally stored SHSH files that you backed up with Tiny Umbrella
Step 4: Open up Tiny Umbrella and click "Start Tiny TSS Server" (hopefully this will go off without a hitch, but if it says it can't open because Port 80 is blocked, close any applications that might be causing this i.e Skype).
Step 5: This step is optional, but if you want to verify that Tiny TSS Server is working you can ping gs.apple.com and it should return 127.0.0.1 as the result as seen below:
Step 6: Great we are almost done, now simply open iTunes and plug your device in. Shift click (or option click) on 'Restore' (Not update!) and select the firmware file we downloaded earlier.
Step 7: Now let iTunes do it's thing. Somewhere along the line iTunes will pack a sad and give you an 'Unknown error'. Don't worry about this, your firmware file has already been loaded. This error (error 1004) is just a baseband error.
Step 8: Open the latest version version of TinyUmbrella which you downloaded earlier. Click 'Kick Device Out of Recovery'.
There you go, you have successfully downgraded your iDevice firmware using SHSH files.
Please remember, if you have not saved SHSH for previous firmwares you can not downgrade but guess what, what better time than now to save SHSH files for the current firmware.
Whenever you restore a stock or custom IPSW of any firmware on your iDevice, iTunes request Apple servers to sign the IPSW with the ECID (Exclusive Chip ID) of your iDevice which is called SHSH Blob. As soon as new firmware gets released, Apple stops signing your ECID for old firmwares which result in iTunes 3194 error.
If you have already saved SHSH blobs for the firmware to which you want to downgrade and you are still getting 3194 error then it means iTunes is unable to connect to Cydia server. To fix this issue, you can use the following this methods:
Edit HOSTS File on Windows:
Open Notepad. Go to File -> Open... or press Ctrl+O. Now navigate to the following location and open HOSTS file in ETC directory.
Now add the following line to the end of HOSTS file and close the Notepad window. Do not forget to Save the HOSTS file before closing the Notepad window.
Edit HOSTS File on Mac:
1. Click Go -> Go to Folder and then enter path /etc
2. Now open HOSTS file with TextEdit and add the following line with at the end of the file as shown in the screenshot below.
Once you have edited the HOSTS file successfully, launch iTunes and restore the stock or custom IPSW. Hopefully, this time iTunes will not throw 3194 error while restoring the firmware.
Last edited by AppleHacker; 05-15-2011 at 12:09 PM.
The Following 55 Users Say Thank You to AppleHacker For This Useful Post:
Just a quick note. Instead of MANUALLY EDITING the HOSTS file, in TinyUmbrella there is an option in the "Advanced" tab to "Set Hosts to Cydia on Exit" This will allow iTunes to talk to Cydia's cache server rather than Apples cache server.
Ive just followed these steps exactly. And now i cannot exit recovery. When i press Exit Recovery, my iPhone keeps going back to the Connect to iTunes logo after trying to boot. Ive tried leaving it plugged in, Ive tried it with TSS running and without it running. Ive tried unplugging after the screen goes blank and nothing changes. It still wants me to recover my iPhone. Have i missed something, is anyone getting this and have they fixed it or got around it. Im trying to go back to 4.3.3. When 4.2.1 finishes downloading i will try that Firmware but would prefer 4.3.3
Thanks in advance!
Update: 4.2.1 Finished and still having the same issue trying to restore to this version aswell... They were the only 2 FW's my SHSH was able to save. What am i doing wrong? Have i got the wrong download or am i stuck on 4.3.4?
Update: 2 Success! Im now running 4.2.1 with 04.10.01 after accidental upgrade to 4.3.4 04.10.01
SHSH and Tinyumbrella + redsn0w Saved my life (Not really, but i can sleep now considering its 2:10am and i been trying since 6pm)
The Fix: After not being able to exit recovery mode from Tiny downgrading the firmware to 4.2.1 i used the redsn0w jailbreak to jailbreak. I was a bit worried in the process as it took so long to actually progress. Took about 10-15 minutes total. After it finished jailbreaking, it come up into Restore Mode (with Emergency dialling) Nothing was happening, i thought it was still stuck... I then opened up iTunes, it froze... So i unplugged my iPhone, shut and reopened iTunes and it said iPhone Activated Rejoice!
Just finished syncing and getting my songs and stuff back on... However, to my stupidity for not backing up properly, i have lost contacts and game saves.
I have what is prob a dumb ? But I have not been keeping up on the latest jailbreaks since 4.1 just for the fact that it has worked great for me on all my devices (2 ipod touch's, iphone 3gs and 2 iphone 4's). I wanted to get a game but it requires the newer 4.2. So I thought I would get back into it and update to the 4.3.3 version. I have been jailbroke on all the devices since 3.2.1 other then the iphone 4's. When I go to Cydia to check my saved SHSH's all my older devices stop at 4.3. The iphone 4's have the newer ones (4.3.5 etc.) So I was wondering why the older devices quit saving the newer ones even though the devices are still jailbroken? Thanks