Shsh Blobs Info
It is a best practice among enthusiasts to save blobs every time a new iOS version is released, regardless of whether you plan to update or not. The "Nonce" Problem
Apple checks if that version is still "open." If it is, they send back an SHSH blob.
Your device sends its ECID and the firmware version to Apple's servers. shsh blobs
Your device's bootloader checks this blob. If it matches, the installation proceeds. How to Save SHSH Blobs
Popular community tools like TSS Saver (online) or Blobsaver (desktop application) can automatically fetch and store these for you. It is a best practice among enthusiasts to
You cannot save blobs for a version of iOS that Apple is no longer signing. You must be proactive.
Without this digital signature, your device will refuse to boot or install the operating system. Why Do They Matter? Your device's bootloader checks this blob
Apple typically only "signs" the most recent version of iOS (and sometimes the one immediately preceding it). This is known as the . Once Apple stops signing an older version, it becomes impossible for a standard user to downgrade to it. SHSH Blobs are essential for:
