Try to change the com port from com/port1 to com/port2:
dc-tool -t COM2 -b 115200 -x tunnel.elf
If it doesn't work try this:
dc-tool -t COM2 -e -b 115200 -x tunnel.elf
Try other com/ports to see where the coders-Cable is conected, if it doesn't work reboot or PC it may have the com/port with trash data in this way it is int.