Signing & Downgrade

SHSH blobs are Apple’s saved authorization tickets for a specific iOS build. Here’s what they actually let you do — and what they don’t — in plain terms.

Most failed iOS downgrades trace back to one of six causes — signing status, device mismatch, or backup incompatibility. Here’s how to tell which.

There’s no fixed downgrade window — Apple closes signing on its own schedule. Here’s what actually determines how long you have and how to track it.

Two reliable ways to check whether Apple is still signing a specific iOS build before you try to restore or downgrade — no jailbreak tools required.