CÓ PRO NÀO CHECK CÁI NÀY CHUĂ, CHIA SẺ CHO ANH EM VỚI NHEN ^^
http://www.iostweaking.com/2014/03/downgrade-ios-7-6.1.3-6.1.4-to-6.1.2.html
you can downgrade to previous version of iOS without even need of SHSH Blobs and AP Tickets.IPSW tool generates ECID-SHSH blobs using UDID and ECID info fetched from the device and generates a patched .ipsw whichfakes the firmware verification process and
restores your device to previous baseband. iPhone 4 users can now downgrade their device to iOS 6.1.3 or 5.1.1 WITHOUT SHSH BLOBS.
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http://www.iostweaking.com/2014/03/downgrade-ios-7-6.1.3-6.1.4-to-6.1.2.html
you can downgrade to previous version of iOS without even need of SHSH Blobs and AP Tickets.IPSW tool generates ECID-SHSH blobs using UDID and ECID info fetched from the device and generates a patched .ipsw whichfakes the firmware verification process and
restores your device to previous baseband. iPhone 4 users can now downgrade their device to iOS 6.1.3 or 5.1.1 WITHOUT SHSH BLOBS.
...
...