The operating system pairs a USB driver with a USB device by matching the Vendor ID (VID) and Product ID (PID) in the driver with those in the device. By default, the CP210x devices come from the factory preprogrammed with VID=0x10C4 and PID=0xEA60. This is the same VID and PID used by the default Silicon Labs Virtual COM Port (VCP) driver.
The default Silicon Labs USBXpress driver uses VID=0x10C4 and PID=0xEA61. In order to use a CP210x device with this USBXpress driver, the PID on the device should be reprogrammed to match the driver (0xEA61). Here are the instructions on how to do this on Windows operating systems:
Note: This procedure assumes that the CP210x device has the factory VID (0x10C4) and PID (0xEA60).