Even if this box is in fact bricked you should still have a short string in the serial data log. At least a few lines.
If it is completely dead, then have you checked the power supply is working ? Are you actually getting power to the motherboard ??
Sorry i do not have the box so can not help any further.
hi my dear
power supply is ok cheked out voltage
when flashing bootloader Electricity was suddenly cut
then receiver is dead not work lan usb rs232.... Only LED flashes several times and no