iFaith just updated to version 1.5.6 by iH8sn0w, iFaith 1.5.6 allows you to dump SHSH blobs and create custom IPSW on iPhone 4, iPhone 3GS and iPod touch 4g. You can download iFaith v1.5.6 for Windows for free from direct link below.
iFaith v1.5.6 also add support for the Apple TV 2 5.2.1 firmware. With iFaith you can save SHSH blobs on iPhone, iPod Touch or iPad running a firmware version that Apple stop signing.
SHSH blobs give you the possibility to downgrade and restore iOS that is no more being signed by Apple. For instance, Apple is presently signing iOS 6.1.3, therefore if you’re attempting to downgrade to earlier iOS version you’re going to get error 3194 on iTunes. That’s essentially Apple suggesting that you simply cannot downgrade your iOS. However, by utilizing SHSH blobs, you are able to trick iTunes to permit your device to become downgraded.
What’s new in v1.5.6:
1.5.6: After Cydia’s mishap with aptickets from 6.0 –> 6.1.2 (causing soft-dfu loops), iFaith now includes an apticket validation. You can utilize the check by browsing for blobs when building a signed IPSW or by downloading existing blobs from Cydia’s/iFaith’s SHSH server under iFaith’s “Show available SHSH blobs on server” button.
1.5.6: Now dumps iOS 5.2.1/6.1.3 blobs on 3GS/A4 devices.
Download iFaith For Firmware Downgrade