A firmware update is available to address flickering or connectivity issues with the HDMI 3 and HDMI 4 ports powered through MST. 

What does this firmware update address?

For customers experiencing flickering or connectivity issues with the HDMI 3 and HDMI 4 ports of the UD-3900C4 docking station on their Windows laptop, this updated firmware can help stabilize this behavior. Please note that if you are seeing problems outside of the HDMI 3 and HDMI 4 ports on the dock, we encourage you to reach out to us at support@plugable.com in order to troubleshoot.

Who should apply the firmware update?

The firmware update is targeted for Windows users only, experiencing flickering through the HDMI 3 and HDMI 4 ports of the UD-3900C4 dock. If you aren't experiencing any issues, we would recommend not taking action on the firmware update.

How do I apply the update?

1. Please download the firmware update utility on your Windows USB-C or Thunderbolt 3 computer
2. Extract the folder named "UD-3900C4_Firmware_Update" from the zip file above to your preferred location, e.g. your "Documents" folder or Desktop
3. Ensure that the Plugable UD-3900C4 dock is connected to the Windows laptop using the included USB-C cable, with at least one monitor connected to the HDMI 3 and/or HDMI 4 port. Please ensure that these HDMI displays are active and running
4. Navigate into the "UD-3900C4_Firmware_Update" folder, then launch VmmDPTool64.exe
   • You may be prompted by Windows Defender SmartScreen that it has prevented an "unrecognized app" from starting. You may click "Run anyway" to proceed
5. Click on the "FLASH" tab, then select the "Load to FLASH" button, which will then prompt you to select a firmware file to load.
   
6. If necessary, navigate back to the "UD-3900C4_Firmware_Update" folder, then select the file titled: UD-3900C4_Ver5_06_101_Firmware.fullrom
   • Upon selection, the firmware update process will automatically start
     
7. Once complete, you will need to power-cycle the dock to complete the update. Simply disconnect the power adapter for the UD-3900C4 (the blue light on the front of the dock should turn off), wait 10 seconds, then reconnect the power adapter
8. Once the dock and any connected displays are reconnected, double-check that the firmware flashed successfully by navigating back to the VmmDPTool64.exe application. Click on the "Debug" tab, then click on the “FW version” button, which will load a chunk of text in the "Status" field. Make sure the "Firmware version" listed is 5.06.101 (refer to screenshot below)