Download Apple iPhone 5s GSM IPSW Flash File:
How to Restore Apple iPhone 5s GSM using itunes:
- Install iTunes on PC.
- Use USB cable to connect phone to PC.
- Connect Apple iPhone 5s GSM to pc holding Home Key, while connecting phone it should vibrate.
- Choose Restore iPhone on itune, it will erase all the data and will install the firmware.
- Hold Shift Key and select ipsw file.
- Click start, When flashing is completed plug out usb cable & boot phone holding power key.