Apple strictly controls the iOS ecosystem by restricting which software versions you can install on your iPhone or iPad. If you are trying to downgrade your device or fix a bootloop using an older firmware file, you have likely encountered Apple's "signing" restriction.
Searching for a "free unsigned IPSW restore tool" will lead you to dozens of paid, heavily marketed software suites (like Tenorshare ReiBoot, iMyFone Fixppo, or Dr.Fone). unsigned ipsw restore tool free
Run a command similar to this:
It uses previously saved SHSH blobs (digital signatures from when the iOS version was still signed) to trick your device into accepting the older firmware. Apple strictly controls the iOS ecosystem by restricting
If you meet the requirements above, several free, open-source utilities can help you execute the restore. 1. Futurerestore (The Gold Standard) Run a command similar to this: It uses