Bios flash; how long

I tried to update the BIOS on my 6400 from A11, I think it was, to A17 using the HDD method. I got a screen saying it was "preparing to upgrade" or something of the sort and then it just seemed to freeze. No screen updates and no HD activity. I,left it for an hour or so and still nothing happened. I have a slight memory that the update ought to give progress reports along the lines of "erasing data" and "reflashing..." but nothing of the sort occurred.

 

Eventually I gulped hard and hit the off switch.

 

Yep. New motherboard. I'm now back to A09 and absolutely terrified of trying to upgrade again. I still have the A11 and A17 exes on the disc but nothing will tempt me to run them until I have an idea of what went wrong and some notion of how to prevent it.

 

First question is, did I bail out too soon? Is it possible that the upgrade would have happened if I'd just waited a bit longer?

 

Or, was I asking for trouble using the HD method? I seem to recall Dell recommend running it from the desktop, but I ran it from my download directory on a logical 'E' partition. Does that make any difference?

 

Lastly, can I create a bootable USB thumb drive and run the upgrades from there? Would that help?