Does anyone know offhand what causes long boot times on the Fenix5, and the same happens after the USB disconnect
Over a minute to power-on. Maybe longer.
There are less than 60 activities on the watch which I know is a choking point for the Fenix even twenty-five firmware versions later
I suspect it is something corrupted.
The USB FAT passes a chkdsk so I know it's not the filesystem.
I suspect it's some app or some other data it doesn't like and waiting for a timeout, or it's scanning a bunch of something.