Latest update broke the thunderbolt display port on my Inspiron 5402

Hello,

Inspiron 5402 does not contain a thunderbolt 4 port but it does have 1 USB 3.2 Gen 2 Type-C port with DisplayPort and PowerDelivery number 5 in the image.However the D nexto your usb-c port means displayport not thunderbolt.

You can recognize thunderbolt ports via the lightening icon displayed next to thunderbolt ports

It is possible a bios update is causing issues  see  Downgrading the System BIOS on a Dell System  however be warned a bios update usually fixes discovered security holes.

Thunderbolt has been broken here since last June on my Dell G511. One of 2 things appear to have broken this. Either 1: a bios update (maybe although downgraded the bios and that didn't fix the issue). or 2: the VBIOS_Flash_ZPE display firmware update. Wasn't able to test this as unfortunately it isn't possible to downgrade this once it has been updated. Dell are offering to take one of the machines back in order to test if they have broken firmware and replace parts although not sure if this will address this particular issue.

To clarify further. I have to Dell G511's here manufactured at different times and both are exhibiting this particular issue.

True however, this won't address the fact that thunderbolt is broken on some Dell laptops such as my Dell G511.

DisplayPort is a standard used to connect displays to computers. It is similar to the HDMI standard, and both standards have similar performance.https://veepn.com/blog/the-ultimate-guide-on-vpns-and-your-connection-speed/ 

My bad. You are indeed correct and both systems in question are G 15 5511's with the RTX 3060 GPU. That's why I suspect that the VBIOS_Flash_ZPE update broke Thunderbolt support back in June as it was working fine until that update and a bios update were applied on both systems. However, I was able to downgrade the bios on one of the systems in order to see if that would address the issue in question which it did not.

If they're offering to investigate, take that offer and send the system in.

You haven't specified much as to what "broken" means -- is there no output through the Thunderbolt port at all, or is there, and something specific just isn't working.

There is no G511.  There is a G 15 5511 model, and if it's that one, the Thunderbolt port is equipped on systems only if the GPU is the RTX 3060.  Systems with the RTX 3050 or RTX 3050 Ti have USB-C 3.2 ports, but no Thunderbolt support.

Is this a G15-5511, and if it is, which GPU do the systems in question have?

Correct. Thunderbolt doesn't work at all although USB-C does through that port. Going to take a look at the service report before doing anything else because if that states that thunderbolt is working then there is no point sending in any of the systems.

OK. Took a look at the service report. They replaced the motherboard and ran it all through tests and sighted that there was a USB failure. As I suspected even though they have done all of the above, Thunderbolt still doesn't work at all. Not sure what else to do at this point. Could send in the system but that was returned here yesterday. I wish someone over at Dell would look at this VBIOS_Flash_ZPE update as it is either that or a bios update that has broken Thunderbolt. Furthermore, my son has the same system and his is exhibiting the same issue and yes, Dell also looked at that system as well.

If these are monitors equipped with native Thunderbolt ports, do they work independently when connected directly to the system?  Other test:  do they work when connected with a different thunderbolt to HDMI hub?

No I am not using displays. I am using Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapters and Apple Thunderbolt to FireWire Adapters and all firewire devices are powered and as I say this was all working until June last year. Tested these devices on Windows 11 on a sepearte desktop and they are still working fine. Also swapped out these devices for others of the same type and they now don't work when attempting to use them with the Dell G15 5511 PC's. They don't even try to connect so the issue is with the Thunderbolt port on these systems.

Hello,

You are complaining thunderbolt is not working as it should but G15 5511 only has thunderbolt support when the gpu is NVIDIA GeForce RTX 3060 look here if you don't believe me.

Correct. However, both of the G15 5511's in question have the NVIDEA GeForce RTX 3060 GPU and Thunderbolt worked perfectly until June 2022. See the rest of this thread for details.

It certainly is a long time. I appreciate that sometimes a bios update or firmware update to the GPU such as the NVIDIA-GeForce-RTX-3060 can break things and I would have thought that Dell would implement some kind of roll back program in order to assist with troubleshooting in the event that something goes wrong. However, for Dell to replace the motherboard, reimage the system and then say that everything is working without taking basic steps such as uninstalling the Thunderbolt drivers then try to reinstall them is unbelievable. My reason for suggesting uninstalling the drivers is that if you attempt to reinstall them after uninstallation they won’t install. I have pointed this out to Dell and the fact that thunderbolt drivers will not install after uninstallation further points to thunderbolt being broken on the G15 511. When I purchased my system Thunderbolt didn’t work then either. However, Dell addressed this in a bios update and it was working fine until June 2022. Don't get me wrong, I think the hardware in these machines is excellent. However, I won’t purchase a Dell machine ever again having paid for Thunderbolt a feature that I would like to use and am unable to use.