The most common reason is attempting to install an iOS version that Apple is no longer signing. Once signing is closed, a standard restore to that version is impossible without previously saved SHSH blobs. Outdated Software:
Above the shelf, he taped a sticky note that read:
It started with a notification on his iPhone: “A new iOS update is available. iOS 15.8.3.”
Before we dive into the solution, it's essential to understand what SHSH and 3utools are.