1. It seems to me that it would be better to read such a firmware file one
   time and free it after use than to waste a chunk of memory (even if paged
   out) for ever.
   u

some drivers need to reload the firmware "semi-often".  ie, when
my iwi(4) craps out, reloading the firmware fixes it usually.  so
getting rid of it isn't always isn't a good idea.