The uptime reported on the balena dashboard is actually most accurately the “network uptime”, in that the device may have been powered up but disconnected from our network (and thus we count that as “down”). You can check the device’s actual time since boot by either:
running the uptime command in the host OS shell
if the uptime command is not available because the OS is old, you can simply run stat -c %z /proc/ to see when the device booted
Once you are logged into the device’s host OS, you should be able to view system logs via journalctl to understand what has caused the disconnection or reboot. If the device is consistently rebooting, we recommend enabling persistent logging.