XPS 9380 Function keys BIOS settings reversed

Hi, got my XPS 13" 9380 Ubuntu-edition last week and I truly love it. They only thing I needed to change was the BIOS setting for the function keys, so that the classic/"real" function keys is the default. Everything was working flawlessly until yesterday when a BIOS/Firmware upgrade arrived. After applying it, I discovered that my function keys had reverted, e.g. pressing F3 increases the speaker volume and I have to hold down Fn to activate the "real" F3. But I had not changed anything in my BIOS settings :-( So I restarted and on a lark tried changing back to "secondary"-option for the function keys in BIOS, i.e. the BIOS setting so that F3 increases the speaker volume. But anyway, after restart I'm back to real function keys, i.e. I have to press Fn-F3 to increase the speaker volume. This looks like a bug to me.