In one embodiment, circuitry on a device is configured to detect a power failure of the device, inform a cellular modem of the device of the power failure, and supply capacitive reserve power to the cellular modem in response to the power failure. The cellular modem of the device may then send, using the capacitive reserve power, a cellular detach message into a cellular network, where the detach message has an indication that causes a receiving device to send a notification of the power failure to a configured endpoint device.