What is SHSH Blobs?
December 2, 2010 in Basic Information by
What is SHSH Blobs?
SHSH Blobs is simply a piece of file which used by iTunes to verify the restore progress. Every time you are doing a restore on iTunes, it will ask verification to Apple server, as the result, SHSH Blobs generated (if the iOS is eligible to restore) then the restore may continue.
What is SHSH Blobs used for?
SHSH Blobs is used for downgrade iOS firmware on iPhone, iPod Touch, or iPad.
Why do I need SHSH Blobs for downgrade?
Because Apple disabled this feature.
This is a war between Apple and Jailbreak community.
Downgrade without SHSH Blobs was allowed in the past, mostly done for jailbreak purpose. But later, Apple disallowed users to downgrade to prevent users from jailbreaking their device.
And then jailbreak community found a way to downgrade to iOS version by using SHSH Blobs. SHSH Blobs generated during the verification process between iTunes and Apple server. This verification required each time you are doing restore through iTunes.
So, by saving SHSH Blobs file on your computer or ‘another server’ and tell iTunes that your computer or ‘another server’ is a (fake) Apple server by modifying hosts file, then you will be able to downgrade. By tricking iTunes that way, you are ‘allowed’ by iTunes to perform restore, which supposed to be disallowed by real Apple server.
The ‘another server’ term here refers to Apple fake server that designed to verify that restore process could be continued. This server could be Cydia’s server, or your own computer (by running TinyUmbrella software), or other else.
How-to Downgrade without SHSH Blobs?
Downgrade iPhone, iPod Touch, or iPad without SHSH Blobs could be possible on the following devices:
- iPhone 2G
- iPhone Touch 1st Generation
- iOS 3.1.3 and olders versions can be downgraded without SHSH Blobs (SHSH Blobs only applies starting from iOS 4.*), but you will need older iTunes version as well, though.
How-to Save SHSH Blobs?
Please see our iPhone Tutorial section.
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