- Go to "Developer options", and enable
- USB debugging
- USB debugging (Security settings)*
- Reboot phone (otherwise enabling the security settings doesn't seem to take effect)
- Connect to ADB an run
Code:adb shell settings put global hide_gesture_line 1
Now the gesture bar is gone, and the change seems to persist after rebooting the phone too. You can also turn off USB debugging.
*This will require you to sign into a Xiaomi account, and you need to have a SIM card inserted for this to work.