I tried to update the firmware version but there was a power outage during the process. After that the device could not be turned on. The pictograms do not light up. The device no shows signs of life. I checked the power adapter, it is good. I tried holding the reset button for 15 seconds (and 30 sec), but nothing happened. I unplugged the power adapter for an extended period of time, but nothing happened. I have no idea what can I do  :(

Do you have any idea?