On a sunny day (Sat, 30 Jun 2018 18:20:17 +0000 (UTC)) it happened bob
prohaska  wrote in :

>From time to time I'd like to mount FreeBSD ufs filesystems on
>a Pi3 running Raspbian Stretch. It appears that FreeBSD's ufs
>filesystems aren't recognized.
>
>There's a reference on the web to mounting ufs on Ubuntu, but
>that's not obviously applicable. An apropos search comes up empty.
>
>Thanks for reading, any guidance appreciated!
>
>bob prohaska

man mount says loo at /proc/filesystems
on my older raspi it says:
 root@raspberrypi:~/compile/pantel/ip_to_country# cat /proc/filesystems
nodev   sysfs
nodev   rootfs
nodev   ramfs
nodev   bdev
nodev   proc
nodev   cgroup
nodev   tmpfs
nodev   devtmpfs
nodev   debugfs
nodev   sockfs
nodev   pipefs
nodev   anon_inodefs
nodev   rpc_pipefs
nodev   configfs
nodev   devpts
        ext3
        ext2
        ext4
        vfat
        msdos
nodev   nfs
nodev   nfs4
nodev   autofs
        f2fs
nodev   mqueue


So no ufs listed.

It also says (the man page) that it depends on the kernel,
so you would have to recompile the kernel to add it.
Maybe that Ubuntu article does just that?
Then you may need to get the kernel sources too,
may as well upgrade if a later version exists.
FWIIW

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