TBT3-UDZ second HDMI port not working with 2020 HP Spectre X360 (Intel Iris Xe)

A month ago, I bought 8 docking stations to pair with brand new Spectre X360 laptops with Intel’s 11th gen Intel Iris Xe graphics.

For the past two weeks since I’ve hooked up these docks, I’ve been experiencing major issues with the second display attached to the dock.

When one monitor is connected, there is no issue. But as soon as a second monitor is connected to the second monitor port, either by HDMI or DisplayPort, the monitor blinks every 15 seconds on average. I recorded a video of this behavior if you would like me to include this.

I have tried with multiple monitors, cables, and different laptops, and I can say with confidence the symptom is not related to a bad thunderbolt or display cables, or other bad hardware.

When I connect the second monitor directly to the thunderbolt port using an active thunderbolt to hdmi adapter, the display works normally, even with the dock connected.

I had a similar issue with a new Dell Inspiron 5406 2-in-1 (also with Intel Iris Xe graphics); however, the issue went away when the graphics driver on Dell’s website was installed.

The Intel Iris Xe driver currently installed on the HP Spectre X360 is With this driver, the display blinks every 15 seconds. I attempted to update the graphics driver to the latest driver from Intel’s website ( released 1/20/2021, but the issue is made even worse. Instead of blinking, there is no display on the second monitor. The monitor is still detected in the Windows display settings, and I can drag windows to the display, but there is no picture out. The monitor simply enters sleep mode.

While I cannot say for certain the cause of the issue, there appears to be some incompatibility between drivers and with the way the dock is handling extracting the two Thunderbolt DisplayPort MST streams. While different products, I have tried using a CalDigit TS3 dock, which contains one DisplayPort output and one Thunderbolt output, and when I use an active adapter on the Thunderbolt output on the CalDigit dock and the DisplayPort output simultaneously, I do not have any issues.

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Thank you for contacting Plugable support! Sorry to hear about this issue. I’d be more than happy to assist you.

At this time we are tracking some issues with laptops and the new Iris Xe graphics, most of the issues have been with HP systems so far. We have found that there does not seem to be a stable driver for these systems and there have been other reports of issues like you’ve described with the second display (or even both displays blacking out or flickering).

We’re working to report these issues to Intel’s Thunderbolt 3 team so that it may be investigated, but I do not have any time frame to offer. I’d be curious to know which model Spectre you have so we can include that data in our report. We may ultimately need to consider offering a return for a full refund for these docks due the instability with these Iris Xe based HPs.

“I have tried using a CalDigit TS3 dock, which contains one DisplayPort output and one Thunderbolt output, and when I use an active adapter on the Thunderbolt output on the CalDigit dock and the DisplayPort output simultaneously, I do not have any issues.”

I suspect the CalDigit dock is using the older Alpine Ridge Thunderbolt 3 chipset based on the output configuration. We have docks using the AR reference design and they should also work with Iris Xe without issue, but for the newer Titan Ridge docks which have additional hardware to enable USB-C host compatibility I believe is where the issues are coming from (addition of DisplayPort MST hubs, though, in Thunderbolt 3 Mode the MST hubs would be working in SST).

Please don’t hesitate to let us know of other questions.

Thanks again for contacting Plugable support and best wishes!

Joshua Henry

Senior Engineer | Product Owner
Plugable Technologies

Thank you, I appreciate the reply.

I’ve had this issue with both Dell and HP with 11th Gen CPUs and Iris Xe graphics. The issue with Dell was temporarily resolved with an old driver on Dell’s site only. The HP driver does not work, by contrast.

However, I have a new development which has me incredibly confused. Of the 8 identical laptops I bought, two of them don’t have this issue at all. They were all deployed at the same time, with the same drivers and updates. Do you know why this would be an issue on some laptops, but not others?


Model: HP Spectre x360 Convertible Laptop PC 13t-aw200 CTO

Date put into service: 12/25/2020

Graphics chipset: Intel Iris Xe
Current graphics driver: (installed by Windows Update)

Graphics Hardware IDs:

Thunderbolt Controller driver: 1.41.987.0 (Windows Update)

Thunderbolt Hardware IDs:

I will follow up with another post later, as soon as I receive back one of the laptops with the compatibility issue

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Thank you for providing this information. We really appreciate that.

Of the 8 identical laptops I bought, two of them don’t have this issue at all. They were all deployed at the same time, with the same drivers and updates. Do you know why this would be an issue on some laptops, but not others?

This is quite strange, I’d probably check to see if the UEFI BIOS revisions match between the working and non working systems as a first step.

Best wishes,

Thanks @Joshua_H

I finally have both HP Spectre laptops in my possession… And I have an interesting discovery.

Laptops which do not have display issues when connected to the Plugable TBT3-UDZ:
BIOS Revision: F.07
Thunderbolt Controller: NVM29.06
Embedded Controller: 31.20

The laptops where the external display flickers:
BIOS Revision: F.10
Thunderbolt Controller: NVM34.01
Embedded Controller: 31.30

All the other firmware is otherwise identical. Including drivers.

I can also confirm that both laptops work flawlessly with both the Caldigit TD3 and older Plugable TBT3-UDV docks.

The full Product Name of each computer is “HP Spectre x630 Convertible 13t-aw200”

The Product Number is 8WP89AV

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Thank you so much for this data! So far we’ve not had any customers with multiples of the same system where one works and one does not, so this data is quite useful.

It would appear there may be a regression with the newest BIOS that HP is offering on these systems and that it may not specifically be related to the Iris Xe graphics as we’d initially suspected.

I’d probably recommend to see if HP support can offer any guidance on a backflash procedure for the BIOS since that’s usually not something that can be easily accomplished (downgrades are often blocked), and to report this behavior to them. I think the goal here will be to (for the moment) get these systems running BIOS F.07 since we know that works correctly.

Edit: Our TBT3-UDV dock and I believe also the Caldigit are both Intel Alpine Ridge based versus this new TBT3-UDZ dock which is Titan Ridge based. I’m curious if HP is currently testing with any Titan Ridge docks in their BIOS validation process, but they may not be able to offer this information publicly.


I’ve just come across this thread as am experiencing almost the identical issue. I’ve a new HP Spectre x360 with the 11th Gen chipset just like the first poster – Model 14-ea0018tu. And just received today the TBT3-UDZ dock which I’m using with two identical BenQ monitors via HDMI, but one of the monitors continually and randomly flashes on and off and it is related to being connected to the HDMI port 2 (upper port) on the dock as I can replicate the issue by swapping cables so it isn’t a specific monitor or cable issue. I’ve an older HP Spectre x360 laptop (8th generation) and it works fine with the dock and monitor setup so certainly seems to agree with the thread above that is related to the new HP graphics or Bios set up? My Bios version is F.09. Any further information that I can provide and advice you can give to help resolve this? Many thanks. Tim

Edit: So an update to this. I managed to seek out the original F.07 Bios and was surprised that I could install this without issue and yet, the flashing monitor is still happening…

Hi Tim! (@Astera) We’ve received your email with the diagnostics. I’ll take a look to see what we can find out and if there are any suggestions we can make.


This is very interesting! I have not been able to get my hands on that BIOS, so can you upload it somewhere or post a link to where you got it?

Also, can you go into your BIOS and post the following info:

  1. On the Main screen, what is the “BIOS Revision”
  2. On the Main screen, use the arrow keys to select “Device Firmware Revision” and press Enter. What are the versions of the Embedded Controller, GOP, USB Controller, and Thunderbolt Controller?

While I don’t want to jump to a conclusion yet, I am wondering if downgrading the BIOS did not downgrade the firmware of the controllers. And that would suggest the issue is not the HP BIOS but a compatibility issue between the controller firmware and controller.

This would also explain why I experience very similar issues on different brands of laptops. I have screen flickering on the 34.01 Thunderbolt controller on a new Dell laptop. Obviously different BIOS and different manufacturer, but same controller and firmware version.

Happy to help! My laptop probably shipped with the F.07 Bios but I updated it on the first day I had the laptop with a few other things via the HP Support Assistant. I couldn’t see F.07 listed on the software for my machine on the HP site, but tracked it down from here http://www.laptopdriverslib.com/2020/12/hp-spectre-x360-14t-ea000-drivers.html

Seeing as it didn’t work though, I then updated the Bios again to the latest version of F.09 though I did confirm though the update through to F.07 on the Bios startup screen. So for the info you’re after:

BIos revision: F.09
Embedded Controller: 40.43
GOP: 17.0.1042
USB Controller: 51
Thunderbolt controller: NVM 34.01

And yes, you may be on to something with TB controller as that didn’t change when I went back to F.07 as I did take note of that seeing as you listed the version of NVM29.06 as working fine. Like you too, I can get the second screen working by using my second TB port and running it straight to the screen via a USB-C to HDMI adapter, but a little ‘messy’ with having to plug and unplug two cables every time I want to free the laptop.

Any way to rollback the Thunderbolt Controllers I wonder??

It’s possible, though this may be tricky…

Some manufacturers have separate Thunderbolt firmware updates (like Lenovo and Dell), where others may roll it into the BIOS update process (looks like HP is doing this from the information provided here in this thread).

Since it looks like the Thunderbolt firmware was not downgraded when F.07 was flashed back onto the system, I suspect there are checks in place where if rolling back the BIOS, the Thunderbolt firmware is probably ignored due to being a newer version already installed (or possibly it just silently errors out as this isn’t an expected or common scenario to roll back to an older version). HP would likely need to provide you with a dedicated Thunderbolt firmware flashing tool, the older Thunderbolt firmware file, and instructions on how to manually perform this process outside of a BIOS update scenario.


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