A Chromecast Master Reset is simply a full factory reset, but it stresses the fact that the device is being restored to its original condition, irrespective of the process of restoring it. Doing this via the Google Home app or simply pressing the actual reset button on the Chromecast hardware until the LED flashes, the result is the same: the device will lose all the personalized information and will need to be reconfigured as an entirely new device.