Activate USB debugging
Settings > About Phone > Tap MIUI Version several times to enable Developer Options.
Go Back and browse to Additional Settings > Developer Options and Enable
- USB Debugging
(- Install via USB) Optionnal - USB Debugging (Security settings)
- Enable view attribute inspection.
Now open command prompt. Type the following codes:
adb devices
adb shell
settings put global tether_dun_required 0
reboot