f you need to restore the iPhone to its original state the process requires iTunes. This can be useful for troubleshooting to see if a problem is hardware or software related. The process can also reset an iPhone for resale, wiping all personal data from the device.
Should you suspect a hardware issue with your iOS device, Apple will normally recommend a complete restore to see if this clears up the problem. You can save time when you go to the Apple store by trying a complete restore first. Restoring will update your iPhone firmware to the latest version.
If your iPhone is booting to a black screen you need to follow additional steps before restoring your iPhone. See these additional instructions by clicking here.
1. Connect your iPhone to the computer and open iTunes.
2. Make sure your iPhone is selected from the left menu in iTunes.
3. Click the Restore button in the center of the iTunes Summary tab.
4. You can choose to Back Up the contents of your iPhone to the computer.
5. iTunes will ask if you're ready to Restore the iPhone, this will wipe all of your data and settings from the device. Click Restore.
6. iTunes will download, prepare and restore the software on your iPhone. Do not unplug the iPhone from the computer during this process!
7. When finished, iTunes will ask if you want to restore from backup. Choose "Set up as a new iPhone" to start fresh with factory settings.
8. Enter a name for your iPhone and the process is complete.