We have already cited enough reasons to you about why should you save SHSH Blobs before updating to latest iOS iPhone firmware. Firmware Umbrella is a SHSH grabber tool that allows you to save your SHSH blobs, required to downgrade iOS firmware and rerun the jailbreak on your iPhone, iPod Touch or iPad incase you unintentionally upgrade to the future firmware releases by Apple.
Note: Make a practice of saving or taking back up of SHSH Blobs [ECID SHSH] on current installed iPhone iOS firmware, before you update your iDevice to newest firmware.
Steps to save SHSH Blobs (ECID SHSH) files on Windows
Step 1 : Download Firmware Umbrella [TinyUmbrella] from here to your Desktop.
Step 2 : Right Click on umbrella-4.00.80.exe and Choose Run as administrator. If you get a Windows Security Alert, make sure both boxes (Private and Public networks) are checked, and hit Allow Access.
Step 3 : You will be prompted to connect to a device. TinyUmbrella will then detect the type of device and its firmware.
Step 4 : Check the Advanced Options box. Make sure that the ECID for your device is coming correctly and then select the correct firmware version, and select ‘Cydia’ as Location.
Step 5 : Press the Save My SHSH button. It is important to note that you can only obtain SHSH BLOBS for the latest iOS firmware version released by Apple.
Once completed you will be notified that it was successful. “You have saved your SHSH locally and the request was sent to CYDIA. This means that CYDIA DOES have your SHSH. Do NOT bug semaphore about the Cydia home page showing this version.”
Important: Sometimes due to server overload SHSH blob are not saved through Cydia. In such case you must save and take backup of SHSH BLOBS locally. In order to do that, just change the Location dropdown to Apple (instead Cydia, as in Step 4) and click the Save My SHSH button again. If the file that gets saved is anywhere from 60-65k bytes then the file should be just fine.
Note: Mac users can follow complete guide posted here on how to take backup of SHSH Blobs with the firmware Umbrella Tool.
Download TinyUmbrella to Save SHSH Blobs on Windows
Via - iclarified