Several people have reported difficulty flashing firmware on macOS High Sierra because the
device port filename doesn't match the serial number from system_profiler. In particular,
system_profiler would return a string ending in `E` whereas the device filename would have
a `1`. This change adds a check for that filename explictily.
I also corrected the location_id fallback (the substring should have been just 3
characters long, not 4), and it works properly on my system if I make the device shortname
7 characters long, and the filename reverts to using the location id instead.
Last, I added one more check, simply listing the filenames, and searching for a match for
the string `kbio01`, which should be present (although in one case, it wasn't).
Michael Richters