You must be logged in as root. Prepare file path or URL of SSH public key.
Download and run the mfsBSD-based installer for FreeBSD-13.1, with root-on-ZFS.
wget https://depenguin.me/run.sh \
&& chmod +x run.sh \
&& ./run.sh [ -d ] [ -r ram ] [ -m (url of own mfsbsd image) ] authorized_keys ...
You must specify at least one authorized_keys source, both URLs and local files are supported.
Wait until the script reports SSH to be available (takes a few minutes) then connect.
ssh -p 1022 mfsbsd@your-host-ip
Once logged in, you can
sudo su - to root without a password. You cannot login as root.
If you have trouble with the connection, wait 2 minutes and try again.
Install using zfsinstall
Install using prompted dialog, or unattended install, with bsdinstall