Over the years, Apple has this strategy of signing / un-signing firmware versions to ensure that iOS users are using the latest firmware files. Once Apple has stopped signing a firmware version, you won’t be able to downgrade to that firmware, at least not through regular means. We have received a report that Apple has stopped signing iOS 8.4. This means that if you are on iOS 8.4.1 and want to downgrade to iOS 8.4, know that you’ve just missed that train.
For jailbreak users this is quite relevant because it has been confirmed in iOS 8.4.1 that Apple has patched the TaiG exploits used to jailbreak iOS 8.4. Basically, if you have updated your iDevice to iOS 8.4.1 you have effectively killed your jailbreak. And now that Apple has stopped signing iOS 8.4, you won’t be able to downgrade to it in order to re-jailbreak. At least, not until jailbreak groups are able to successfully jailbreak iOS 8.4.1. To easily check which firmware versions are still being signed by Apple, use this URL.
This is hardly a surprise since Apple almost always stops signing firmware versions several days or weeks after a new version has been rolled out – in this case iOS 8.4.1. Aside from ensuring that all iOS devices are updated, it is also a strategy to keep jailbreakers at bay. So if you are in iOS 8.4.1 now and want to jailbreak, your only option is to patiently wait for jailbreak groups to jailbreak iOS 8.4.1. But with iOS 9’s release just around the corner, it’s an unlikely possibility.
So to make sure that you don’t make the mistake of killing your jailbreak, always confirm if the latest firmware update is jailbreak friendly or not. [via iPhoneHacks]Contact Us for News Tips, Corrections and Feedback