It seems the Dell service, while suggesting me to update the SK hynix ssd firmware on my xps 13 9360 because of an issue I have, does not provide a way to update it in ubuntu or dos or winpe. I know winpe was available up to version 20004A00, but my drive already has 20005A00 and SK hynix only provides a windows installer, without stating the latest version, and they don't answer to my emails...... It seems the only way to actually find out if there is an update is to clone the drive, install a rogue windows for the time it takes for the update, and then restore ubuntu... which is a bit of a drama.

So maybe someone with windows knows if 20005A00 is the latest?