Is there a specific problem that you are trying to fix with a BIOS update? MY point is that if you keep trying to update the BIOS and problems continue to occur then only bad things can happen. If the system is working fine and you are happy with the operation then my advice is leave well enough alone. The forum is full of posts where a BIOS update went wrong and bricked the MB.
I have a Dell XPS 15 9500.  I am trying to update to the newest 1.16 BIOS.  I believe it's currently 1.15.1. I first tried via Dell Command Update and then via Support Assist.  I then later simply ran the .exe file I downloaded from the Dell site.  Lastly I put it on a flash drive and used the F12 key at boot so try and install from BIOS and installing from the Flash Drive. Each time the result was the same.  It goes into the screen with the Dell logo and says "updating your firmware.  Do not power down your system".  It simply says flash in progress and stays at 0%.  I know it's not supposed to be restarted but at some point I've restarted.  I'm able to use my computer fine.  I just don't seem to be able to update. Any ideas on how I can update?  I have done many firmware updates and never have had an issue before until now.  
Unable to update BIOS on Dell XPS15 9500