I was having USB issues on a new XPS 13 9380.  Has ran all the updates available a month ago then installed Ubuntu.  USB issues cropped up intermittently when attempting to use an external cellular modem.  Attempted to update bios, but all updates appear to require windows, even the ‘universal installer’ ones.  No bios files that could be loaded using the tools in the firmware appeared to be present.  Poked around the return page and found:

https://www.dell.com/learn/us/en/uscorp1/terms-conditions/art-us-return-policy:

Systems configured with an Intel® 8th Gen or later CPU are designed to run optimally with the Microsoft Windows 10 operating system. Removing the factory-installed operating system to run a non-Windows 10 operating system (such as Windows 7 or Windows 8) may make the product ineligible for return to Dell for a refund or cause system instability and performance issues that may not be covered by your warranty, support, or service agreements.

So the question is, has dell ceased to support non-windows systems even at the most trivial level by providing firmware and bios updates?