You can download the iPhone Firmware Flash Tool from the following links:

These are paid software suites (with free trial features) designed to fix iOS system issues without data loss in some scenarios.

The blue progress bar on the monitor had been stuck at 64% for three hours. Outside, the neon signs of the city blurred through the rain-streaked window of the repair shop, but inside, the only light came from the terminal window and the glowing apple logo on a bricked iPhone 15.