I'm having the same issue on my XPS 15 9560 as well. I'm getting inverted color output through the hdmi port. I hope there's a quick fix. I cannot work on this kinda environment........
Just contacted Dell support about this problem, and here is their answer:
"Thank you for reaching out to us. We do not have any known issues with this system. As you have issues with the display, we recommend you to install the latest drivers from our support webpage."
So, basically Dell gives me the middle finger.
I've escalated this issue to our engineering group. I'll update you all as soon as I get anything back from them.
Could you send me a PM with your service tag and email please?
I just bought a TB16 for my 9550, and am going through the initial driver-update process. The first one I did was to update the Thunderbolt driver to yesterday's 4.26.03.001. The .exe ran, and came back with "Thunderbolt Firmware Update failed" dialog. The dock is NOT connected, I am just preparing the system to set myself up for success here. I'm not sure whether the FW update actually applied or not bc of the error.
After the update, I went into Win10 System Information, Software Environment, System Drivers, and see that "Thunderbolt Controller" Status is "Started" "Manual" "Running" "Degraded".
What would you recommend I do at this point? How do I check if the TB update really did not apply? Should I get the penultimate release and install that, then proceed with updating all the other drivers per the user manual? I intend to us the dock with a DELL U2718Q @ 4k60 (which should work with either DP or HDMI), 1g ethernet, and audio usb interface.
I already have latest BIOS 1.5.1. I'm running Windows 10 Pro Version 10.0.16299.
I saw the linked support page for the 9550, but am confused as to how to grokk it - i assumed it's point was to convey the "recommended configuration" however for each sw package/driver/component, there are several "recommended" items. What gives?
@Timblaktu: I guess your problem is not related to the Thunderbolt firmware update we are talking about in this thread.
I have a TB15 dock and the new thunderbolt firmware works nicely with it. It is really just related to the laptop internal HDMI port.
This firmware update rendered one of our XPS 15 9550 laptops unbootable. The update progress bar reached 100% and prompted for a restart. I clicked OK and the computer never booted again. It gets pas POST and the Dell logo but hangs at either a black screen or on the Windows logo with no progress. Onboard Diagnostics still work and show no errors but I can't boot from USB or from the internal NVMe drive.