At first,please make sure VCC 5V for the USB is avaliable.
If still can discovery the Udisk,please check the welding between the Core Module and the Connector.
At last if all above is not working can you connect four wires(5V,D-,D+,GND) from the CORE module to the USB Connector.Here(GitHub - domino-team/domino-hardware) you can get the schematic.