⤳ Activate visibility option in Mi Fit
(Work without activate this option for me).
⤳ Open Notify and Fitness for Mi Band.
⤳ Accept localisation authorization
(Pass "import save", "authorize access at notifications").
⤳ Expand the menu with icon at left top, and go in "Settings".
⤳ Scroll down in "Basics" tab, and at "Mi Band firmware version" tap on "Update".
⤳ Accept the required authorization.
⤳ Choose "Custom firmware" and choose your firmware file.
⤳ Tap on "Start update".
⤳ After Mi Band 3 reboot, Mi Fit will connect automatically at your Mi Band 3.
⤳ Uninstall Notify and Fitness for Mi Band.