With tools like Prometheus (futurerestore), you can downgrade to an unsigned iOS version only if you have saved blobs containing your ECID and the specific iOS version’s build number. An ECID check here verifies that the blob matches your exact hardware.
| Need to do this... | Use this... | Where to find it? | | ----------------------------------------------------- | ------------------------------------------------ | ------------------------------------------ | | Check warranty | Serial number only | checkcoverage.apple.com | | Save SHSH blobs for downgrade | ECID (hex or decimal) | TSS Saver, blobsaver | | Jailbreak using checkm8 (pwned DFU) | ECID | iDeviceReRestore, pwnedDFU tool | | Report a lost device to police | Serial number (IMEI also recommended) | Original box or Apple ID | | Verify if a used iPhone has mismatched logic board | ECID + Serial number via GSX (paid service) | Third-party GSX providers | | Restore a bricked iPhone without blobs | ECID is NOT enough; you need Apple’s signature | You cannot—only Apple can sign current iOS | ecid check iphone serial number
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If you have the ECID but not the serial number, you cannot directly derive the serial number from the ECID. However, some paid third-party services (e.g., GSX database lookups) can map ECID to serial number using Apple’s internal records. Two numbers appeared on her screen: If you