How to Downgrade iPhone 4 from iOS7 to iOS6.1.3 without SHSH Blobs
 

Some users want to downgrade iPhone 4 from iOS7 to iOS6, but Apple has closed its signing. Actually iPhone 4 with SHSH backup can be downgraded to any compatible firmware using 3uTools. But what should you do without SHSH backup? This tutorial can guide you to downgrade iPhone 4 to iOS6.1.3 without SHSH blobs.

Why iOS6.1.3? Because 3uTools Pro Flash supports iOS6.1.3 flash without SHSH blobs, and provides the “forced iOS downgrade”.

http://www.3u.com//upload/20170119/1...1109082273.png

Please note that after the forced downgrade, you should use “3uTools tethered boot” to start your iPhone after it’s turned off.

Notes before downgrade:
Please backup your phone data before downgrade.
Turn off “Find My iPhone” , or you’ll need to use Apple ID to activate your iPhone after flash.
Download the latest 3uTools.

Part A: iOS downgrade

Part B: Jailbreak and tethered boot

http://www.3u.com//upload/20160413/1...3747052497.jpg

Part C: Install plugin “Insomania pro”

http://www.3u.com//upload/20170119/1...3501094074.png


Check original post on 3uTools clearly: How to Downgrade iPhone 4 from iOS7 to iOS6.1.3 without SHSH Blobs

3uTools, so powerful~