Hello,in this post i will show you how to downgrade iPhone 4s from ios 7-8-9 to iOS 6.1.3
Please use step by step to finish process without errors
THIS TUTORIAL IS FOR WINDOWS ONLY ! I don't have mac
USE AT YOUR OWN RISK !

1.First jailbreak your iPhone


2.Install openssh from cydia


3.Download custom ipsw fom this LINK (fistmedaddy.ipsw) 922MB


4.Download Telemach from this LINK  (Telemachus) 10.6MB


5.Open telemachus and make it like image and press start

Telemachus have to start idevicerestore,you don't need anything to do
Just wait for magic
After finish restoring process,you will need to set up like new phone
And ... iOS 6.1.3 is here