Some iPhone users looking to update to iOS 8.4 before the signing window closes have had trouble finding the correct IPSW. While these files are normally available directly from Apple, in some cases they must be downloaded from a mirror.
Downgrade to iOS 8.1 (or upgrade, for that matter) is no longer possible. Two weeks after the release of iOS 8.1.1, Apple has stopped signing the previous version. The move comes as no surprise, as the company has been known to stop signing IPSW files just days after a new release.
Those seeking to install or restore iOS 8.1 will have to use iOS 8.1.1 instead. The news comes hot on the heels of an iOS 8.1.1 jailbreak solution released by TaiG team. Despite the 8.1 signing window closing, users looking to jailbreak their iOS devices can use the TaiG jailbreak tool to jailbreak iOS 8.1.1.
The iPhone 6 Plus was released with iOS 8.0, a 5.5-inch Retina HD display and A8 processor. Apple's largest smartphone to date, the iPhone 6 Plus packs a larger battery than the iPhone 6 and features optical image stabilization. Here are links to the official IPSW files for the iPhone 6 Plus:
iPhone 6 Plus iOS 8.1.1: iPhone7,1_8.1.1_12B436_Restore.ipsw
The iPhone 6 launched along with iOS 8.0, a 4.7-inch Retina HD display and A8 processor. There have already been several updates and bug fixes issued for iOS 8. Here are links to the official IPSW files for the iPhone 6:
The iPhone 5s was the first iPhone to feature Touch ID. The iPhone 5s was originally released with iOS 7 installed. Here are official iOS 8 firmware / IPSW files for the iPhone 5s: