This directory contains a cut-down GENERIC kernel configuration file 
intended for the RPI3. /usr and /var are on USB flash, /tmp is on the
microSD card. Two  1 GB swap partitions were tried, one on the microSD
and one on the USB flash drive. MicroSD swap turned out to be a very
bad idea and was disabled, so the system is running with only 1 GB of
swap on the USB flash device.

ls -l on the kernel reveals
bob@www:~ % ls -l /boot/kernel/kernel
-r-xr-xr-x  1 root  wheel  7139016 Feb 23 18:06 /boot/kernel/kernel
A generic kernel is about 12 MB, so the size reduction is appreciable.

Uname -a reports

FreeBSD www.zefox.org 12.0-CURRENT FreeBSD 12.0-CURRENT #2 r329880: Fri Feb 23 18:04:57 PST 2018     bob@www.zefox.org:/usr/obj/usr/src/arm64.aarch64/sys/ZEFOX  arm64

svnlite info /usr/src reports
Path: .
Working Copy Root Path: /usr/src
URL: svn://svn.freebsd.org/base/head
Relative URL: ^/head
Repository Root: svn://svn.freebsd.org/base
Repository UUID: ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Revision: 329893
Node Kind: directory
Schedule: normal
Last Changed Author: cem
Last Changed Rev: 329892
Last Changed Date: 2018-02-23 17:58:53 -0800 (Fri, 23 Feb 2018) 

It boots and runs, but seems to bog down to a
crawl when running make -j4 buildworld. However, response to new logins
on the serial console and ssh sessions appears normal and fast.

A copy of the console output reveals an odd "stutter", but that _might_
be an artifact of the terminal server, which is a Pi2, also running
a custom kernel, which seems to be stalled in all ways _except_ for 
the ssh/cu session providing console access.

Rate of progress on j4 buildworld seems uneven; overnight the log file grew
to less than 2 MB, then in slightly over an hour it apruptly progressed to
more than 9 MB. However, it hasn't crashed yet 8-)