I fixed it only after a reset to factory of the edge. Then I have been able to repair with the mobile. In any other condition the Bluetooth icon did not light up on the Edge. Considering again a wipeout of personal data screen after 10.0 upgrade via PC, the upgrade process doesn't seem to have been ...upgraded. Cheers
Similar issue. After the firmware upgrade, the unit will not sync with Garmin Connect (IPhone, iOS12.1). I get 2 devices in my Bluetooth Control Panel: ""BT_Edge Explore 820" and the other says "Edge Explore 820." I cannot delete one without impacting the other. The latter automatically appears when setting up the devices, and "insists" on being paired. My guess is that this is causing confusion with the app and / or device. I have done a partial reset and a factory reset, with no improvements. Currently working on a rollback solution.