External Monitors not working on USB-c. Elitebook 645 G9 Notebook

[GJM13]

Good morning,

I have a Elitebook 645 G9 Notebook. The HDMI port on the device works with an external monitor. However, the usb-c will not connect any external monitors. I've plugged them directly into it and also used a known working HP Puck or docking station that it came with. The docking station works on other devices. It also works with the keyboard and mouse on this device. Just no displays will show. I have deleted,installed, and updated the drivers and re-imaged the device. still no luck. We have a ton of elitebook 645 g9 notebooks with no problems. Except this one. Any help would be greatly appreciated. I am thinking I might need to replace the mainboard.

[Fwanck]

While not exactly the same problem, my Elitebook 860 G9 has similar problem. Monitors whille flicker/trun off/lost signalusing a USB-C dock.

I did not have this problem with my previous G6 laptop.

We are also seeing this happend to EliteBook 840 G9 laptops.

We are fully updated an no fix.

We have sent a unit in at HP for diag/replacement.

[HolgerAxelgaard]

We are seeing the same on HP 645 g9, it happens on both HP and other brands of docks/monitors. Screen flickering in and out when connected to USB-C. Peripherals that are connected to the dock continue to work, but the screen flickers. 

[GJM13]

Do you know if there is a fix yet?

[HolgerAxelgaard · Accepted solution]

I was able to improve this on the USB-C G5 docking station by upgrading its firmware, however, it continues to be a problem on other docks, like DELL. 

[GJM13]

If you don't mind me asking, can you tell me how you upgraded the G5 docking station's firmware? That's what I have too.

[HolgerAxelgaard]

Sure, here it is. Connect the dock, run the file. Wait while it completes and dont touch your pc or disconnect the dock. Takes about 3-4 mins and everything will flicker. 

Driver - HP USB-C-dockingstation G5 | HP® Customer Support