We were parsing the disk number out with:

  dunit=`echo $disk | sed -e 's/..\([0-7]\)/\1/'`

which works fine with "ad0", giving a dunit of "0"
but with "ada0" you get a dunit of "a0"

And, after misinterpreting through another sed command:

dunit=`echo $dunit | sed -e 'y/01234567/abcdefgh/'`

we get "aa" instead of "a". Append that to "sd" and your disk
becomes "sdaa" instead of "sda". Next thing you know I'm blaming
Emacs for inserting an extra character in /etc/fstab!