Dell XPS firmware upgrade


Discover shows me that there’s an update available for my Dell XPS, but when I try to update it, nothing happens, I am not even requested for the root password to install it, and no error info is produced.
Any idea how to get some info for troubleshooting/alternatives ways to update the dell firmware?

I have found this page on the dell website: and installed DSU instead, but when I use it I get this error:

DELL EMC System Update 1.9.0
Copyright (C) 2014 DELL EMC Proprietary.
Do you want to import public key(s) on the system (Y/N)? : y
Unable to read public file /usr/libexec/dell_dup/0x756ba70b1019ced6.asc
Importing public key(s) failed
Exiting DSU!

any help would be greatly appreciated