The device shows mac address of 5E:CF:7F:xx:xx:xx My router WIFI connection log shows 5C:CF:7F:xx:xx:xx
Displaying the incorrect mac address can cause the device to not connect if anyone wants to setup mac address filtering on their router which I have done on mine for increased security.
It appears that the GMC-600+ incorrectly reads WIFI module mac address OR some of the mac address data is hard coded and the rest pulled from WIFI module. I did a little web search for 5C:CF:7F mac address and it belongs to Espressif Systems which is a WIFI and Bluetooth chipset manufacturer in Shanghai. Did the same search for 5E:CF:7F and it came up as unknown. Just to refresh your mind this is the mac address displayed by my GMC-600+.