How to Downgrade iPhone 3GS iOS Firmware from 6.1.6 to 6.1.3 - YouTube
How to officially downgrade your Apple iPhone 4s to iOS 6.1.3
Jailbreak definitivo firmware iOS 6.1.2 su iPhone (5, 4S, 4, 3GS) iPod Touch (4G, 5G) e iPad mini e iPad (2, 3, 4 retina Wi-Fi e 3G) unthetered con evasi0n [MAC & Windows] | Featured
Download iOS 6.1 Firmware For iPhone, iPad And iPod Touch
question] how do i fix restore needed on iphone 3gs (literally on every firmware i tested) 3.1.3,4.1,6.1.6 : r/LegacyJailbreak
iOS 6.1.6 on the iPhone 3GS : r/ios
Developer creates a way to downgrade the iPad 2 and iPhone 4s to iOS 6.1.3
iOS 6 IPSW [Direct Download Links] | OSXDaily
Jailbreak iPhone 3GS/iPhone 4 on iOS 6.x Using Sn0wbreeze Custom Firmware
Apple stops signing IOS 6.1.3 for iPhone 4S | MacRumors Forums