@Hhaghgou here isn't a thread to cry, that's not our fault if you installed a Firmware that bricked you're smartband, by installing a Beta Firmware you know the brick risk.
By reading previous comments you can see that's not the first Firmware that brick the device, but to know that it require read...
By the way, we're not responsible for your bricked device and we're not Huami or related to Huami. If there is somebody who find a solution it will be shared here, but at moment there isn't, so like I already said use warranty or wait for next Mi Fit version.
Now, please understand we can do nothing more and be patient... Thanks.