The honest answer is . The glory days of easy downgrading are over for modern devices (iPhone XS and newer, A12+ chips).
In those days, jailbreaks were not "semi-untethered." They often exploited specific bugs in specific iOS versions. If you accidentally updated from iOS 9.1 (jailbreakable) to iOS 9.3 (patched), you lost your jailbreak forever.
While saving SHSH blobs sounds foolproof, Apple has made downgrading increasingly complex over the years by introducing two security hurdles: and SEP . 1. APNonce (Anti-Replay Nonce) shsh blobs
For long-time iOS enthusiasts and jailbreakers, "SHSH blobs" represent the ultimate key to device ownership. If you have ever updated your iPhone to a new iOS version and immediately regretted it due to bugs, battery drain, or a lost jailbreak, you have likely looked for a way to go back.
The process is technical, but it generally involves: The honest answer is
./futurerestore -t blob.shsh2 --latest-sep --no-baseband target.ipsw
Apple uses this system to ensure that devices remain on the most recent, secure version of iOS. By "unsigning" older versions, Apple effectively prevents users from downgrading to software that may have known security vulnerabilities or lack the latest features. For most users, this is a background safety feature, but for the jailbreaking community, it is a significant barrier. The Role in Jailbreaking and Downgrading If you accidentally updated from iOS 9
A popular online tool where you enter your device’s ECID (a unique identifier) to save blobs.
Forcing users onto the latest update ensures that the maximum number of devices support newer app developments and system features.
An SHSH blob (Signature HaSh blob) is a unique digital signature that Apple uses to approve iOS installations. Think of it as a one-time digital passport issued by Apple's servers.
SHSH blobs are highly specific. They are generated using your device’s unique hardware identifier, known as the (Exclusive Chip ID). Because the blob embeds your specific ECID alongside the specific iOS firmware version, a backup of an SHSH blob from one iPhone will not work on any other iPhone in the world , even if they are the exact same model. Why Apple Uses Signing Windows