Updating FreeBSD on armv6 board (RPI-B)

One of my old home automation boards running ebusd is still using Raspberry PI 2 B SoC. FreeBSD is still perfectly supporting this hardware, however, due to being a Tier-2 platform, binary updates freebsd-update are not supported. Of course, one can download the new image, but this will mean re-installing and reconfiguring all the software, which is time-consuming and painful. Also, the traditional build from source" way will probably take forever on this tiny board and also could potentially destroy the SD card. So the obvious alternative was cross-compilation.

If you're in this very specific niche - you're very happy this guide exists.