The release of macOS 26 Tahoe enables high refresh rate modes for HDMI 2.1 4K resolution displays, including additional features like Variable Refresh Rate (VRR). Plugable adapters with compatible chipsets, such as USBC-HDMI8K support these higher modes. Some units may require a firmware update to enable this functionality. Please also note that high refresh rate and Variable Refresh Rate modes are not available on all displays. Consult your monitor’s user manual to check if your monitor supports these features.

Our USBC-HDMI8K adapter uses a Synaptics VMM7100 chipset, and in order to update the firmware please download the VmmDPTool64 application. At this time the firmware update can only be applied using a Windows computer.

To begin the firmware update process please go through these following steps:

1. A Windows PC must be used for the firmware update process.
2. Download this VmmDPTool64 updater software from the Windows Microsoft store: https://apps.microsoft.com/detail/9pmrbpftmtmc?hl=en-US&gl=US             
3. Download this firmware file: VMM7100 update FW20250919
4. Connect the USBC-HDMI8K adapter to your computer
5. Open the VmmDPTool64 application
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6. In the FLASH tab - select Load to FLASH
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7. Select the firmware file within that downloaded folder named ‘XL4L7100_250918.fullrom’
8. Wait for the tool to finish updating
9. Power cycle the adapter by disconnecting it from the computer for one minute
10. Connect the USBC-HDMI8K adapter to your Mac and a compatible HDMI 2.1 display
11. Navigate to the ‘Systems Settings’ app
12. Navigate to Displays - select the external display
13. Variable Refresh Rate (40-144 Hertz) will now be available along with other static high refresh rate mode
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Those steps will complete the high refresh rate firmware update for the Plugable USBC-HDMI8K HDMI 2.1 adapter on macOS 26.