I have a brand new CCR-1036-EM that I attempted to apply the latest firmware to (6.44.3) and after the router rebooted it would start services and then reboot as long as an Ethernet cable was plugged into the router. If I unplugged all Ethernet cables it would boot successfully but as soon as I plugged in an Ethernet cable it would reboot again.
same here - use NetInstall with instructions