When Apple stops signing a particular firmware, it removes the sign (signature) from the firmware so users won't be able to downgrade to it. These blob files are the digital signatures that Apple places on each IPSW firmware file for each iOS device. You learned earlier that it is possible to restore unsigned IPSWs with the help of SHSH2 Blobs.

You will learn more about these requirements in this blog.

To downgrade to a previous iOS firmware that has stopped being signed by Apple, part of the requirements are a third-party restore app, the destination unsigned iOS IPSW file, and its SHSH blob file. Anyone trying to install unsigned IPSW firmware will only get an error message. Usually, when you want to upgrade or downgrade to an iOS version using the IPSW restore file, you will do so through iTunes.ĭuring the downgrade process, iTunes will make some verifications and checks with Apple servers to ensure you are restoring a signed IPSW file. Yes, you can restore your iOS device to an unsigned IPSW firmware, but not in the traditional way. Part 2: Is It Possible to Restore to Unsigned IPSW? To resolve firmware update bugs and issues, reverting to a previous stable iOS version might be the solution. New versions of iOS software often cause unpleasant experiences to device performance and features. iOS users wouldn't be able to use iTunes to restore to an unsigned firmware.Īpple periodically unsigns iOS version because of security issues and encourages users to make use of additions newer updates have to offer. An unsigned IPSW means Apple has stopped supporting the iOS version. IPSW is the file extension of Apple's iPhone mobile operating system.

Part 2: Is It Possible to Restore to Unsigned IPSW?ģ.1 Restore Unsigned IPSW Using SHSH2 Blobsģ.2 Restore Unsigned IPSW by FutureRestoreīonus: How to Downgrade iOS with WooTechy iMaster

Reiboot import local firmware