You will need to be in DFU mode (Recovery) on your device, which bypasses the iOS boot loader, and connected to a computer with iTunes for the recovery procedure. This procedure is not the same as restoring a firmware within iTunes which allows the boot loader to check and authenticate attempts to downgrade or install invalid firmware. 0. Download the IPSW file for your particular iPhone, iPad, or iPod. You should be able to find these files with a search engine. Just make sure to hash check the file. After downloading it, then copy the file into the correct iTunes directory for your Windows OS or macOS version. (This step is not necessary because once the device is connected to an internet enabled computer and recognized by iTunes in DFU mode, then the program will download the appropriate IPSW file from Apple servers.) 1. Connect your device to a computer with iTunes and allow the program to recognize the device. 2. Power off your device. 3. There are multiple methods to enable the DFU mode of different Apple iPhones, iPads, and iPods. Use a search engine to verify the procedure for your particular device. 4. Once the device has entered into DFU mode, identified by a blank screen and a message by the iTunes program, then it will begin downloading the most current general release firmware for that device. If you downloaded the IPSW file, then you should have already copied that file into the appropriate iTunes directory and it will use that file for recovery after validating it. 5. Once the recovery procedure has completed, then you will be left to setup as a new device or to restore from a backup.