If your iPhone won’t turn on, then you may quite rightly feel rather frustrated – but the good news is there’s no reason to panic right away. Sometimes the iPhone can be a little temperamental, and there are a few things that you can try to jolt it back into life before you resort to contacting Apple or asking a Genius to take a look at it.
Firstly, check to see whether it’s actually charged. If you’ve gone a while without charging it the battery might be completely dead. Plug it into the charger and leave it for several minutes. Does it start to show charging progress on the screen? If so, resist the urge to switch it on right away. Let it fully charge before you turn it on and start using it again.
If it hasn’t come on after charging, try restarting it. Hold the power button in for a few seconds. If the phone was off, hopefully, it will turn on. If it was on, then it should restart.
If your phone remains unresponsive, then the next option is a hard reset. This will reset the device’s memory (but won’t wipe any photos, music or other data held in the phone’s storage). To reset the phone, hold down the power button and the home button. If you have a newer phone that doesn’t have a home button, such as the iPhone 7, then hold down the power button and the volume down button. Keep holding them for 10-20 seconds. If you see a shut-down slider, this means that your phone was actually on, but keep holding the buttons anyway.
Wait for a white Apple logo to appear, then release the buttons and let the phone start up.
If that doesn’t work, it could be that your phone is flat but that the charging cable you’ve been using doesn’t work. Try a different power socket, and a different charger and cable.
DFU Mode and Factory Reset
These two options are a last resort. If your phone is non-responsive, plug the cable into the lightning/dock connector port, and then hold the home button down (or on newer iPhones, the volume down), and then while holding the home button down plug the other end of the cable into your computer. Hopefully, this will put the phone into recovery mode so you can restore it.
If you can’t even do a restore, then try putting your phone into DFU mode. Plug your iPhone into your computer, and hold the power button for three seconds, then release it. Next, hold the power button and the home (or volume) button for ten seconds. Release the on/off button but keep the home (or volume, if you don’t have a home button) button held down for five seconds. The screen should stay black, but your computer should have opened iTunes, and if you follow the onscreen instructions it will work you through restoring your phone.
Sometimes, the phone is working, but the proximity sensor isn’t, so the screen stays dark, even when the phone is on. If you restart the phone, it should work long enough to go to settings > general > reset and then ‘Rest All Settings’ to erase your preferences and fix any sensor issues.
If all of the above fails, first, check the latest updates, and if it doesn’t help, then you will need to take your phone to the nearest Apple Store and get them to look at the issue – they may be able to fix it for you, or otherwise help you to get a new phone if it’s under warranty.