The brief period (usually days or weeks) when Apple allows both a new and a previous iOS version to be installed. How to Save Your Blobs
To circumvent this limitation, savvy users and developers have developed methods to save and use SHSH blobs to downgrade their devices. Tools like TinyTurbine, tsschecker, and others allow users to save the SHSH blobs for their devices on their computers. These saved blobs can then be used to "fake" the signing process, enabling users to downgrade their devices to previously authorized firmware versions.
Because Apple only issues blobs for currently signed versions, users in the jailbreaking community "save" their blobs while a version is still signed. shsh blobs
When updating an iOS device, the device checks the new firmware's SHSH blob against the one provided by Apple. If they match, the update is deemed legitimate, and the installation proceeds. This mechanism ensures that only authorized firmware can be installed on a device, safeguarding against malicious or compromised software.
You cannot simply take a saved blob from a hard drive and paste it into iTunes. Apple’s server doesn’t accept pre-played tickets. This is where the concept of (Number used once) enters. The brief period (usually days or weeks) when
: Apple only signs the latest iOS versions. Once they stop signing an old version (usually weeks after a new release), you can no longer get that "ticket" from them. The Solution
To use your saved blobs, you typically need specialized tools like . This tool "tricks" the device into accepting the saved blob and the corresponding IPSW (firmware) file during a restore. These saved blobs can then be used to
You do not need a jailbreak to save blobs. You only need your device’s (a 16-digit or longer hex number).