FYI, users who got one of the first batch ITead Sonoff Zigbee 3.0 USB Dongle Plus (which has Silabs CP2102 USB-to-UART bridge with programable EEPROM) report that ITead has, unfortunately, forgot/missed or chosen not to configure their own custom “Product Description” string to it. 
That means that those cannot use USB discovery even though their hardware supports it, which is a real bummer. IMHO potential buyers should really write to them and ask them to configure this on them.
This would not be hard for ITead to fix as all they need to do is write their own “description” to the EEPROM of the CP2102N USB-to-UART chip when they flash the firmware on it before packaging it.