For newer devices (iPhone XS and later), the process requires "nonce entangling," making it much harder for users to manually set the required nonce without an active jailbreak. How to Save SHSH Blobs
Starting with iOS 5, Apple introduced a nonce —a random string of numbers generated for every single restore attempt. This means a saved blob will only work if your device generates the exact same nonce that was used when the blob was originally saved.
