Dell XPS 13 9360 - BIOS v. 2.4.2 breaks UEFI Network Stack Ability

We've tested a number of laptops to see if it was a problem with the hardware.  Every one that we updated broke this feature.  This isn't the first time Dell has messed up a BIOS.  Luckily we only updated 30 of them, we were getting ready to upgrade the BIOS for all of them before we realized the issue.

Regarding the details behind the network boot, generally how it works is as soon as you have an Ethernet adapter plugged in, and you have the UEFI Network stack option enabled, you should see 2 additional network boot options (one for IPV4, one for IPV6).  This occurs whether you have an Ethernet cable plugged in or not.  With this particular BIOS revision, these options no longer appear, regardless of the adapter used, or the settings in the BIOS.

The Ethernet adapters we tested do work fine in Windows, this is only an issue with the UEFI network stack (or possibly missing USB-C drivers from the BIOS that were in there previously).  I know UEFI handles hardware much differently now, allowing you to inject drivers into the firmware for devices to use.  If that's the case, this version of the BIOS doesn't have the drivers needed.

Either way, phone support seems to have problems understanding what the issue is, and who needs to know about it and they just send onsite techs rather than kicking it up to engineers who should probably be notified before it becomes a larger issue.  The same thing happened prior to the 2.3.1 revision of this same BIOS.  It wasn't until a large part of the community had issues with their docks that they released the fix.  I'm just looking to get these laptops rolled out again, so unfortunately I can't wait for that.

If you are going to swap out the motherboards anyway, I think I would take one as a test unit and reinstall the same Bios.  On my 9365 is takes a long time for the Bios to upgrade since there are several different entities being updated.  If you try another update, you might try doing it with another system configuration regarding what is attached to it or how it is powered.  Maybe even take one home (I know this sounds stupid but I would try anything possible).

I am sorry I have no experience with a Network boot situation but it is strange such an option would be corrupted..  Does you Ethernet connection work normally otherwise?  Do you have any options as to where or how you access a PXE boot server?

I should add, if the settings mentioned in this thread are where you think they should be then change them, reboot and change them back to where they should be.  There is always a chance something got stuck and the setting is not showing correctly.

Correct, Thunderbolt Adapter Boot Support needs to be enabled too.

Prior to the BIOS update these options were available on all of these laptops, so all of the options (UEFI Network Stack, Thunderbolt Boot Support, tc..) were previously enabled.  Just to be sure, I reset the BIOS defaults, and went through changing the settings one by one to match that is functioning correctly with the older BIOS still on it, but it still doesn't show the network options.

On the system you are testing, are you saying it is a xps 9360 with v2.4.2 of the BIOS, and you ARE seeing the options?  If so, what thunderbolt adapter model are you using?  Maybe it's only certain adapter models that aren't working?  I've tried 2, as mentioned in my original post.

I'm upgrading the BIOS through Windows, and I could try a new file, but I'm worried it will cause yet another laptop to have this feature to be disabled.  I'm assuming overwriting the BIOS would result in that "Unsupported" message again, similar to what I was getting trying to downgrade.  But I'll give that a shot.

Thanks for the suggestions!

I have gone through the enabling the UEFI Network stack and did not see the PXE options until I enabled the Thunderbolt boot support in the USB/Thunderbolt settings.

I noticed, when I accessed the Boot device menu that Secure Boot was disabled.  I may have done that at some time but I do not remember leaving it that way.

Is there any chance use saved the Bios configuration as a special configuration and that is interfering?

Have you tried downloading a new Bios update file?  Possibly the way you are updating your systems is corrupting it somehow?

Hope it works out for you...

And the last thing is a Hail Mary.  The 9365, after the latest Win 10 upgrade build, had a problem with hibernating and shutting down.  The link below took care of the problem.  Read the comments about the vPro provisioning.

www.dell.com/.../how-to-reset-real-time-clock--rtc--to-recover-your-dell-xps--latitude-and-precision-pc

Maybe someone else will have had some experience with your situation.

No, as I mentioned earlier, I am on a 9365.  I was just going through the procedure since I did not see the PXE options and wanted to check why.  I got a Bios update a couple of months ago.

Is your 9360 an 7th or 8th generation processor?

Maybe you are saying the same thing, but on my system I can enable Thunderbolt without enabling the allow for boot option.  Are you using the Thunderbolt port for your Ethernet adapter?  

The model we use is the 7th gen i5 version.

And we are talking about the same thing regarding the thunderbolt option, there is a thunderbolt enabled, and also thunderbolt boot option.  They are both enabled (all I had done on these PC's is upgrade the BIOS from one version to another, I hadn't changed any settings from when it was functional).

Thanks for that link, I'll see if I can somehow roll one back/reset it.

The BIOS is pretty new (only 9 days old) so I'm guessing that's why not many people have experienced this yet.  I'll let them do their hardware swaps and make sure I don't upgrade the BIOS again on these haha.

Just to verify, you mentioned that you had secure boot disabled, by any chance did you have "Legacy Boot ROMS" ENABLED? (Under Advanced Boot Options).

I've never set this option (Legacy Option ROMS) because I always have secure boot on, but I just noticed that enabling legacy allows the UEFI network stack to work.

So I guess now I'm wondering, is SecureBoot no longer supported with UEFI network booting?

No, I never enabled the Legacy boot.  But remember, I do not have any PXE devices to boot from so my system could not check them for compatibility with Secure Boot.

About all I know about Legacy Boot ROMs is when Secure Boot first started, some of the PCIe devices, such as video cards, were not compatible and that option was necessary for booting with Secure Boot.

But at least some progress and more information concerning your situation.. :)

It's not really dependent on the PXE device to boot into, even if I don't have the network connected, it should still show the IPV4/IPV6 options.  The problem is that it doesn't even show those options unless I enable legacy boot rom options (which is unfortunately requiring me to disable secure boot in order to do).

I still can't get support.  Called them with this new information and now they told me that my warranty doesn't cover issues that arise due to BIOS software changes.

So I'm going to let the guy come and change the motherboards and pretend this didn't happen.

I just wanted to pass along, I set mine up again and the Legacy ROMS on my system is greyed out, I cannot check it.  I am still in Secure Boot so the process did not turn that off.

I am going through a TB16 Dock and all its drivers are updated.  If the Thunderbolt works through the PCIe bus, it may be something on your system involved, possibly the Ethernet devices or their drivers or even the Thunderbolt firmware, which has been updated recently.

Of course, none of this really counters the fact a Bios update may be responsible.