Shsh Blobs | [work]

to downgrade or "sidegrade" to that version later, even after Apple has stopped signing it. Jailbreaking

While saving blobs was a "get out of jail free" card in the early days of jailbreaking, Apple has introduced more complex security layers that make them harder to use on newer devices (A11 and later): shsh blobs

Originally, you could set any nonce. Now, the nonce is "entangled" with the hardware. In practical terms, this means you cannot use a blob saved years ago unless your device is currently and you can manually set the boot nonce to match the one in your old blob. to downgrade or "sidegrade" to that version later,

Acts as a unique digital signature for a specific device and firmware. In practical terms, this means you cannot use

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.