We need to put iPhone, iPad or iPod into recovery mode when iOS device is not recognized by iTunes, or totally unresponsive, or when iPhone is stuck on Apple logo. Though recovery mode can restore iPhone or iPad to make it a totally new device, it will delete all data on it. So make sure you have backup your devices in advance.
To put your device into recovery mode, follow these steps:
1. Disconnect your device from the computer.
The process won't work if you start with the phone connected to the computer. Leave the cable connected to the computer, as you will be reconnecting the phone later in the process.
2. Power down your iPhone/iPad/iPod
Press and hold the Sleep/Wake (Power) button for a few seconds until the red slider appears, then slide the slider. Wait for the device to turn off.
3. Press and hold the Home button.
While pressing and holding the Home button, connect your iPhone to computer. When you reconnect the USB cable to iPhone, the device should turn on and display the Apple logo.
Keep holding the home button until the iTunes logo/USB cable appears on the screen. When appeared, you can let it go then. There, you go; the phone is now in recovery mode.
4. Open iTunes
iTunes will launch automatically inform you that your device is in recovery mode and that you need to restore your iOS device.
5. Restore your device
Click on Restore button to restore the device. After the device has been restored, follow the on-screen instructions to set it up, and recover from the backup.
Related Tutorial: How to Exit Recovery Mode with iTunes