If you are going to purchase a new smartphone, you need to carefully check all the components of the device.
Smartphones from Xiaomi have an engineering menu. In it, you can check the device for problems very deeply.
On the Xiaomi Redmi Note 5 smartphone with MIUI 11, the engineering menu has 34 tests: display, gps, sensor, WiFi, etc. .
To start testing the device, enter in the application “Phone”:
Next, run a test of the required device component or start step by step through all the tests starting from the first one.