Monitor Flickering from HDMI Port on TBT3-UDC3 when connected to 2019 MacBook Pro 16"

Last Update: September 14th, 2021
Article ID: 1046910

This is a common issue that many customers have had with the HDMI port on the TBT3-UDC3 when connected to the 2019 MacBook Pro 16". 

We have released a firmware update for the dock that addresses this issue. If you have a Windows system with a USB-C or Thunderbolt 3 port, you can apply it to the dock yourself. Some users have reported that Boot Camp works as well to update the firmware. If you have access to a Windows system to update the firmware, the instructions are as follows:

  1. Please download the firmware update utility here on your Windows USB-C or Thunderbolt 3 computer: Link to download firmware update utility
  2. Extract the folder named “EHDDR1_Synaptics_VMM5320_CLI_20210202” from the zip file above.
  3. Set up the TBT3-UDC3 dock that is to be flashed by connecting it to power, and connecting an HDMI monitor to the HDMI input on the dock. Make sure that the HDMI monitor is active and running
  4. Use the included Thunderbolt 3 cable with the dock and connect the dock to the Windows Thunderbolt 3 or USB-C computer. Make sure that the HDMI display is working before proceeding
  5. Navigate into the “Sys” folder, then launch VmmUpdater.exe
  6. You should see a current “Firmware version” of “5.04.003”. Click on the “Update firmware” button, then select the file named “Panamera_fw_tortilla_5_05_202.fullrom” under the folder of “Sys”
  7. It should take a quick moment to flash, then you should be prompted that the action is completed. Close out of the VmmUpdate.exe application, then unplug power from the dock so that it fully powers off
  8. Wait 10 seconds, then re-plug the power to the dock. Once the HDMI display pops back up, double-check that the FW flashed successfully by launching VmmUpdater.exe once more, and confirm that the “Firmware version” now says “5.05.202”

If you are experiencing these flickering issues with your 2019 MacBook Pro 16" but do not have access to a Windows device to update the firmware, please reach out to us at

Note that this firmware update is only intended to address flickering issues on the HDMI port on the TBT3-UDC3 when connected to the 2019 MacBook Pro 16", and it is not guaranteed to address flickering issues on other devices.