We have tested and verified the following free tools. They range from beginner-friendly GUI apps to complex command-line utilities.
Restoring an unsigned IPSW (iPhone Software) file is a highly technical process generally restricted by Apple’s security protocols. While several free tools exist that claim or possess the capability to perform "downgrades" or "future restores," the success rate is entirely dependent on whether the device has for the specific firmware version. unsigned ipsw restore tool free
Successful restoration of unsigned firmware typically requires SHSH Blobs No A12/A13/A14+ support Requires entering pwned DFU manually