I found an old Beaglebone Black lying around (ashamed to say its been in a draw so long I have no idea what I intended to use it for).

The obvious thing to do was to get OpenBSD on it and make it do some work for me - in this case I'm slowly using Janet to rebuild my own personal software to do various things so I can get off the Cloud and all the BS subscription and privacy-less nonsense.

I followed this Beaglebone Black install guide [1] (approximately) and add below some specific instructions on top of it that worked for me:
- first download the stable 7.6 (or later) image [2]
- get the image on to your installation medium (I used Balena Etcher on MacOS)

Then run the installer on booting and specify:
- HTTP Server? (hostname or 'done') [cdn.openbsd.org]
- Server directory? [pub/OpenBSD/7.6/armv7] pub/OpenBSD/armv7

Everything else was as per defaults.

Its a pretty straight forward process.

[1]  https://wiki.ircnow.org/index.php?n=Openbsd.BBB
[2]  https://cdn.openbsd.org/pub/OpenBSD/7.6/armv7/miniroot-am335x-76.img