Can I Downgrade my IOS on my Iphone 4?

Currently i want to jailbreak my iphone 4 but i'm on 6.1.3 and you can't jailbreak on it! I was wondering how do you downgrade your ios on iphone 4 from 6.1.3 to 6.0 through 6.1.2 so i can use evasion to jailbreak it from there?

Http://www.google.co.in/url?sa=t&rct=j&q=how%20to%20downgrade%20my%20ios&source=web&cd=2&cad=rja&sqi=2&ved=0CDQQtwIwAQ&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DhiL2jb5jNOM&ei=4udcUdSRCsLQrQeF-oH4Aw&usg=AFQjCNFISYkUFAXNV0RqYfQpGQBFJw1wzg&bvm=bv.44770516, d.bmk see this video and downgrade your ios see this too http://www.google.co.in/...v.44770516, d.bmk and this too http://www.google.co.in/...v.44770516, d.bmk