upgrade from memstick?

[Zoran Kolic]

Is it possible to use memstick image to upgrade
freebsd? Like as openbsd has an option using the
bsd.rd file with <upgrade> to do the task?
I'm aware that freebsd-update would be the only
method available. Though not finding it right now,
there might be a way to point the app to the local
device using freebsd-update.conf file?
The reason to avoid net upgrade is sloweness of
the connection.
Best regards

                         Zoran