Electronics Repair Questions? Ask an Electronics Technician
If the connection failed during the firmware update then the system will be unable to boot itself normally again until the firmware is reinstalled manually.
This will need to be done at a Marantz service centre using their specialist firmware installation equipment -
you can contact the Marantz distributor in Australia, Qualifi, to arrange this, at (03) 8542 1144 or *****@******.***