If you are trying to restore an unsigned version of iOS without previously saved blobs, it is generally impossible via standard methods. 10 Common Flashing Errors With Solutions - 3uTools
For the remaining 20%? Apple has simply closed the window. No software, no hack, no fix can force Apple to sign an old iOS version. Your time is better spent finding a saved blob from 2021 than retrying 3uTools in 2025. i unable to request shsh 3utools fix better
Use TSS Saver website. It never fails. And when it does, it tells you exactly why—unlike 3uTools’ vague "Unable to Request." If you are trying to restore an unsigned