03-10-2018, 05:50 AM
this can also happen if the hdd is not externally powered. if powered through usb the hdd might start spin down when the board loses power and then as the board powers again the boot up sequence may not detect the drive since it had begun power down and the boot up process happens faster than the time it takes the drive to spin up and report ready. this may be more of an issue with boot on sd card & filesystem on hdd. if the hdd is externally powered most of the time the drive does not begin spin down immediately. if externally powered and not recognized it could be software as you mention or a sync issue between usb port and drive interface.
