There are a number of questions asking about installing/running FreeBSD on the Pi – it looks like there are a lot of problems. Is FreeBSD runnable on the Pi? How can I get started?
A lot has changed, for the better, since the early days of FreeBSD on the Pi. In my experience installing and running a recent version (11 or 12) is pretty painless these days.
Here are the steps that work for me on the "big" boards – I don't have a Pi Zero so I can't speak to them:
Decompress the image
xz --decompress ...
ddthe image to an empty SD or microSD card
dd if=<FreeBSD image file> of=/dev/<SD card mount> bs=1M
Install the card in your Pi and apply power to boot.
Once the Pi is up and running, login – ssh, keyboard & display, or serial all work (for credentials use
freebsd/freebsd or you can also login with
root/root if you're on a serial line or the keyboard) and have fun.
If you are doing a headless install it may be a trick to get
ssh to connect to the Pi. Find Raspberry PI address on local network gives some good techniques for finding the IP address assigned to your Pi.
Once you have it:
should do the trick.
You can find more info on the FreeBSD Wiki.