After Xiaomi's mobile phone system comes with "system update" upgrade, do you still have the software, phone number and SMS installed in the original system? Or directly initialize?

Updating the system will retain the original data.

The brush will erase all previous data.

Brush machine, the technical term of mobile phone, refers to changing or replacing some original languages, pictures, ringtones, software or operating systems of mobile phones through certain methods. Generally speaking, brushing the machine is to reinstall the system for the mobile phone. Brush machine can make the function of mobile phone more perfect and restore the mobile phone to its original state. Under normal circumstances, the Android mobile phone system is damaged, resulting in functional failure or failure to boot, which is generally solved by brushing the machine. Generally, Andriod mobile phone brushes are divided into line brushes, card brushes, soft brushes and factory brushes.