What should I do if the iPhone 4/iPhone 4S mobile phone is black?

If the system shuts down abnormally, we can start the system directly.

The second scenario is introduced. The DFU mode fails to be started when a problem occurs in the Apple system, but the itunes recovery mode can be used to start the DFU mode. But there is no problem with your mobile phone. If you mistakenly enter the DFU mode, you will not be able to enable it. This is actually a good solution.

You only need to press and hold the power key and Home key at the same time to wait for your iphone to respond. Generally, it takes 10 seconds. If it does not respond for dozens of seconds, don't stick to it, see the following method.

The above is because of the incorrect DFU mode. If it is the third case, you need to enter the DFU mode. How can you enter the DFU mode? First, install itunes on your computer and download the latest ios system. Or there are backup recovery files in advance. Of course, during the recovery process, computers can be connected to the Internet and can be downloaded online. The waiting time is long.

Then connect the black screen mobile phone to the computer with a USB cable, and press and hold the on key and home key for 10 seconds (it is best to make it more accurate) and then release the power key in the tenth second (do not make a mistake) hold down the HOME key. It does not matter if a connection icon or a black screen appears on the screen. Itunes will have a response to the identification mechanism.

 

Then press the shift key on the disk and choose to use itunes to restore your mobile phone. Then, the system prompts that the system will be able to solve the problem after it is restored. This method applies to ipod and ipad.

If the current white Apple, we can press the power and then the home can be turned on, if the power is not fully charged, it is the power supply is broken, we can change a board to solve the problem.

 
If the problem persists, we can check whether it is a hardware problem after sales.