(Signature HaSH blobs). This is a unique digital signature that proves the firmware you are trying to install is currently "signed" or authorized by Apple for your specific hardware. The Breakdown:
SHSH blobs are digital signatures Apple issues for a specific iOS version on a device ECID. Tools like 3uTools request SHSH data from Apple’s servers or third-party mirrors. “Unable to request SHSH hot” typically means 3uTools failed to retrieve the blob because it couldn’t reach the server, couldn’t validate the device info, or encountered a temporary service issue. 3utools error unable to request shsh hot