Why can't Redmi k40 mobile phone be used for no reason?

It is recommended to try the following methods:

1, change the charging method, for example, from charger to computer usb charging, to see if it can be turned on normally. (This is to eliminate the cause of battery dormancy) or unplug the battery and reinstall it to see if it can be turned on normally.

2. It may be a system card. Restarting the phone will solve it.

3. Whether it is possible to enter the recovery period. How to enter the recovery: In the power-off state, press and hold the "Volume Increase Key" first, then press and hold the "Power-off Key", and let go to enter the recovery after the boot screen appears. If you can enter the recovery, please switch the system and back up the recovered data. If you can't succeed, you need to clear all data (address book, SMS, mobile phone application, etc. Will disappear).

4. There is something wrong with the mobile phone system, which cannot be recognized. Whether you can enter Fastboot. Method to enter Fastboot: Press and hold down the "Volume Reduction Key" and then the "Shutdown Key" when the power-on screen appears, and then let go to enter Fastboot. Please connect your mobile phone to your computer and brush a complete system package with Miflash.

5, mobile phone hardware problems. At this time, you can only take your mobile phone to the maintenance office for repair.