When your iPhone is in recovery mode, you can restore and upgrade iOS and firmware or use recovery mode to jailbreak your iPhone. You can easily exit recovery mode manually, if you accidentally put your phone in recovery mode, your phone is stuck in recovery mode, or if you do not want to complete the upgrade you started in recovery mode. Your iPhone should finish an upgrade in recovery mode within an hour, but the time depends on how many upgrades or restores you are performing. You will know your upgrade is complete when the iPhone automatically turns off recovery mode and reboots.
Press and hold the power button on the top edge of the iPhone while simultaneously pressing the home button, which is the round button and only button on the front of the phone.
Wait until the iPhone powers off, and then release the power and home button. It could take around fifteen seconds to power off.
Press the power button again to turn the iPhone back on. When your phone reboots, it will not be in recovery mode.