[floatboth]

FreeBSD does not use vnconfig, FreeBSD uses mdconfig:

    # mdconfig -f smartos-latest-USB.img
    md0
    # gpart list md0
    ...
    scheme: MBR
    Providers:
    1. Name: md0s1
       ...
    # mount -o ro -t msdosfs /dev/md0s1 /mnt
    // (or, use labels)
    # mount -o ro -t msdosfs /dev/msdosfs/SMARTOSBOOT /mnt

Or for ISOs, in one line:

    # mount -t cd9660 /dev/$(mdconfig -f image.iso) /mnt

[jlgaddis]

I was just about to correct your correction, because I can quite clearly recall using vnconfig on FreeBSD.

Apparently that's been a little while, however. According to vnconfig(8):

> The mdconfig utility first appeared in FreeBSD 5.0 as a cleaner replacement for the vn(4) and vnconfig(8) combo.

5.0 was released just over 15 years ago.