FreeBSD 12.1 on Raspberry Pi 3B+, completely headless?

[David Mehler]

Hello,

I've got a Raspberry Pi 3b+ that I'd like to put FreeBSD 12.1 on. It
is completely headless the only thing it has is it's power connection.
I have downloaded and wrote to sd the latest 12.1 amd64 rpi3 image.

As this is headless I have looked and read that the pi 3b+ onboard
wireless adapter is not supported out of the box. Is this so? Is there
a way perhaps with a custom kernel to make this work?

My goal is to drop this sd card in the pi, start it up, and have it
come up on the wireless network and be ready for me to ssh in to it.

Any suggestions appreciated.

Thanks.
Dave.