Shsh Blobs Better -

You can only save blobs for an iOS version while Apple is currently signing it. You cannot "back up" blobs from a version already installed on your phone if Apple has stopped signing it. Popular tools for this process include:

SHSH blobs (also known as SHSH2 blobs or simply "blobs") are small, unique digital signature files used by Apple to authorize iOS firmware installations on specific devices. How They Work shsh blobs

Apple uses this system to enforce software homogeneity. By "unsigning" older versions of iOS shortly after a new update is released, Apple ensures that the vast majority of its user base is on the most recent, secure version of the software. For Apple, this minimizes fragmentation and closes security vulnerabilities. For the enthusiast community, however, this "signing window" is a cage. If a user accidentally updates to a version of iOS that cannot be jailbroken, or if a new update slows down an older device, they are traditionally unable to "downgrade" to a previous version because Apple is no longer issuing the necessary blobs. Saving Blobs: The Escape Hatch You can only save blobs for an iOS