Apple released iOS 7 and later iOS 7.0.2 to the public along with the release of iPhone 5S and iPhone 5C. Developer NotCom has released an update for TinyUmbrella that supports saving the iOS 7.0.2 support SHSH blobs of A4 devices which includes iPhone 4, iPhone 3GS, and iPod Touch 4.
Go through the guide to save SHSH blobs using TinyUmbrella.
As per official blog –
I’ve updated TU for iOS 7.0.2. Your mileage may vary. I fixed the libraries issue. (My mistake!). I’m still working on a fix for iTunes 11.1. I’m pretty sure I know what the problem is. I just need to find a few hours to put the fix into TU.
Keep in mind, this is only likely to work for a4 devices and older. (a5 and newer devices are out of luck) Sorry!
TinyUmbrella lets you save SHSH blobs so that you can downgrade later if required if Apple stops signing the iOS firmware file.
Download TinyUmbrella 7.02.01 for Windows and Mac OS X