XPS 13 9300, BIOS 1.0.10, USB Type-C to DP adapters no longer work

@_Shade_ what version of the Main System TI Port Controller 0 and 1 drivers do you now have? Whatever I try (downgraded the BIOS to 1.0.6), I am stuck with version 1.8.7.39 of those drivers, rather than the previous 1.6.5.36 version, and my adaptor therefore doesn't work, even though the embedded controller is back to version 1.0.1

@_Shade_Interesting, I did a flash back as well and got 1.0.1, but I still experienced the same issue. Repeated re-flashing also did not solve things.

Though, I noted there were certain occassions where a problematic adapter would somehow work, but only temporarily. It would 'reset' thereafter.

I did some tests again and noticed that when the power cable was connected on the left side the USB C to HDMI adapter on the right side was not working properly.
So connect the power cable to the USB-C adapter and wait until the monitor is recognized and then connect the power.

Of course I also tested a USB-C to DisplayPort cable. This works perfectly up-to-date in every situation.

It doesn't matter which BIOS I'm running, the HDMI adapter hits more.

At the end of my test I even had both external monitors connected, one via DisplayPort and the other via HDMI.

DP & HDMI Works

I also tested a DELL DA200 adapter with no problems.Ethernet, HDMI, USB, VGA adapter.

Furthermore I also connected a DELL WD19TB which was recognized and used without any problems.

Unfortunately it is not possible to send more than 60 Hz to the external monitor via these devices.

@AbbasB  yes i have the same firmware as you can see in the screenshot.

@jphughan That's good, but a greater sense of urgency on Dell's part would be welcome given how debilitating it is with so many people WFH and unable to use an external screen due to this problem.

Thank you for pushing and here's hoping they get their skates on with a solution.

@describee  and others, just an update on the escalation report I submitted about this, as I mentioned in a post on Page 3 of this thread.  I just got a phone call from a member of the Customer Quality Management Team about that report.  He confirmed he's the right person to handle cases like this, but since he's going to be on vacation next week, he's going to send it to the "Advanced Resolution Center" before he leaves so that it hopefully gets some traction in the meantime, and then he'll keep working it when he gets back.  Obviously I can't promise any results here, and even if results arrive, keep in mind that this will still likely take time since it will involve identifying underlying cause, developing a fix, testing it, etc.  But hopefully this is at least a step toward resolution.

@jphughan And we appreciate it! Thanks.

@AbbasB  I agree, but unfortunately I am not in a position to set Dell's priorities or their sense of urgency.  I can only advocate and persuade here, which I am trying to do.

Thanks @jphughan ! Even if it cannot be fixed quickly, maybe if they could come up with a way to rollback the full BIOS (including the controller firmware), it would be helpful I guess

Mine is on BIOS v1.0.7 and is working pretty good. Also, works with my 

Mokin MUC0402 6-in-1 USB-C Adapter
- Works, and appears as "USB Billboard Device"
- Has a HDMI-port (4K@30Hz ?), but I haven't tried-it yet.

For those of you involved/following ... What is the consensus here?

Should I stay on v1.0.7 or upgrade further ?

Problems I'm interesting in curing:
- Strangely out-dated Intel-ME (and previous firmwares not updating it)
- Occasional slow booting (even with Toshiba XG6 SSD ) . 

I need the Mokin (or something like it) to keep working.

I haven't had any problems with USB-C hubs/adapters displaying 4k @ 30Hz or below, but you'll run into problems if you try to do 60Hz.

I agree, it should work, but from my experience:

Lenovo Ideapad 730S -> USB-C to HDMI 4k @ 60Hz: Works

Lenovo Ideapad 730S -> CalDigit TS3 Plus Thunderbolt Dock -> USB-C to HDMI 4k @ 60Hz: Works

Lenovo Ideapad 730S -> CalDigit TS3 Plus Thunderbolt Dock -> Active DisplayPort 1.2 to HDMI 4k @ 60Hz: Works

Dell XPS 13 9300 -> USB-C to HDMI 4k @ 60Hz: Does Not Work

Dell XPS 13 9300 -> CalDigit TS3 Plus Thunderbolt Dock -> USB-C to HDMI 4k @ 60Hz: Does Not Work

Dell XPS 13 9300 -> CalDigit TS3 Plus Thunderbolt Dock -> Active DisplayPort 1.2 to HDMI 4k @ 60Hz: Does Not Work

Here's the best part: I paid over twice as much for the XPS 13 9300 than I did for the Lenovo Ideapad 730S...

@faraday7  Useful data point, but 4K 60 Hz even through hubs/adapters should work as long as the hub/adapter you're using supports receiving a DisplayPort 1.3/HBR3 or better signal from the source system.  That allows enough display bandwidth for 4K 60 Hz even when the USB-C link is set up to also carry USB 3.x data at the same time.  The Dell DA300 supports this, for example.  And the XPS 13 9300 supports DisplayPort 1.4.

we're all talking about a standard of thunderbolt 3 and usb c 3.1 gen2 and compatible adapters or accessories just don't work on this ultrabook for around 2000 €.

I can only ask Dell to finally do something about it.
I am a customer who is not currently satisfied with the BIOS updates and the firmware for a high-quality product that is currently in the pocket of any other manufacturer.

@Tesla1856Your issue with the failed Intel ME firmware update is really quite strange, given that I had no issues on my first unit as well as the replacement I received recently.

As for the USB hub compatibility, I think it's hard to say... it's a calculated risk, I guess. If you have a spare HDMI adapter lying around, then maybe I would try the upgrade. Otherwise, I would wait. My latest update is that the following adapters are known to work:

- CableMatters USB-C to HDMI 2.0

- CableMatters USB-C to DisplayPort 1.4

- Choetech USB-C to DisplayPort 1.2