Apple modified the signing protocol. Older blobs just required the ECID. Modern blobs require the generator (a specific nonce).

Originally, you could set any nonce. Now, the nonce is "entangled" with the hardware. In practical terms, this means you cannot use a blob saved years ago unless your device is currently jailbroken and you can manually set the boot nonce to match the one in your old blob.

This is the cruel irony: You need a jailbreak to set the nonce to use the blobs you saved to get a jailbreak.

For the technically inclined, SHSH blobs are deeply rooted in cryptography. The system relies on a challenge-response authentication.

Without a valid blob, your phone will reject the iOS version, even if it is an official Apple file.

Each time an iOS device is restored or updated, the device requests a signature from Apple’s signing server (gs.apple.com). The server issues a signature (the blob) only for the latest signed iOS version. The blob includes:

Without a valid blob matching the firmware, device version, and ECID, the restore fails.

The SEP manages your passcode, Touch ID, and Face ID. When you restore iOS, the main OS and the SEP firmware must be compatible. Critically, Apple signs SEP firmware separately from the iOS system.

If you try to downgrade to iOS 14 using blobs, but the latest signed SEP is from iOS 17, the restore will fail. Your iPhone will bootloop because the old OS cannot talk to the new, incompatible security chip.

Use: TinyUmbrella (pre-iOS 10) or iFaith.

Shsh Blobs

Apple modified the signing protocol. Older blobs just required the ECID. Modern blobs require the generator (a specific nonce).

Originally, you could set any nonce. Now, the nonce is "entangled" with the hardware. In practical terms, this means you cannot use a blob saved years ago unless your device is currently jailbroken and you can manually set the boot nonce to match the one in your old blob.

This is the cruel irony: You need a jailbreak to set the nonce to use the blobs you saved to get a jailbreak. shsh blobs

For the technically inclined, SHSH blobs are deeply rooted in cryptography. The system relies on a challenge-response authentication.

Without a valid blob, your phone will reject the iOS version, even if it is an official Apple file. Apple modified the signing protocol

Each time an iOS device is restored or updated, the device requests a signature from Apple’s signing server (gs.apple.com). The server issues a signature (the blob) only for the latest signed iOS version. The blob includes:

Without a valid blob matching the firmware, device version, and ECID, the restore fails. Without a valid blob, your phone will reject

The SEP manages your passcode, Touch ID, and Face ID. When you restore iOS, the main OS and the SEP firmware must be compatible. Critically, Apple signs SEP firmware separately from the iOS system.

If you try to downgrade to iOS 14 using blobs, but the latest signed SEP is from iOS 17, the restore will fail. Your iPhone will bootloop because the old OS cannot talk to the new, incompatible security chip.

Use: TinyUmbrella (pre-iOS 10) or iFaith.