Zbook Studio G10 wrong resolution with G4 Thunderbolt dock

[Martin838]

Hi,

I'm using a Zbook studio G10 (sku: 7C9K8AV) with a Thunderbolt G4 dock. I have 2 monitors connected to the dock with DP cables both monitors are 1440p but I can't select anything higher than 1080p. 

Steps so far taken are:

Updated firmware of dock to 1.5.25.0 Rev.B ( the newest firmware on HP website)

Updated Nvidia driver

Updated Intel Iris Xe driver

Set the bios to: Enable High Resolution mode

When I change 1 of the displays to HDMI cable it will get the 1440p while still using the dock, but the other display will stay at 1080p. And when I use a different laptop (not an HP one) both displays work with the DP cable at 1440p.

According to these HP document it should work:

https://www8.hp.com/h20195/V2/GetPDF.aspx/4aa8-1295enw 

https://h20195.www2.hp.com/V2/GetPDF.aspx/4AA5-2657ENW.pdf#:~:text=HP%20ZBooks%20support%20multiple%....

Any tips that I can try are very welcome, I have been trying to make this work for about a day now

 Thanks!

[Martin838]

Little update:

I got a USB-C to HDMI cable and used that in the display alt USB-C port on the dock and the other monitor on the HDMI port of the dock. Now both displays have 1440p @100Hz (120 or 144Hz didn't work for both). Still I'm very confused why this doesn't work with the DP cables (I checked the cables, they are labeled DP1.4) So any tips are still very welcome!