The following text was directed to bugs.pcbsd.org, but the invisible parts seem to go both ways:
Stretch does not see PC-BSD and PC-BSD does not see Stretch or Jessie.
My experience with PC-BSD 10.2 and Debian Stretch have been a new and
different experience. With my old Dell Inspiron laptop, I started with
Linux Debian Jessie and Stretch with Grub in between. I tried using the
Stretch and Jessie versions of zfs system. It had problems, so I installed PC-BSD
in the Jessie partition. The installation went fine, but PC-BSD version
of grub appeared to install just fine, except the grub boot screen said
Stretch was the only choice!
Mmmh... Maybe install again. Same results. One boot choice.
Well, take it from the other side; install PC-BSD on the whole
harddrive and redo grub to see the Stretch partition. PC-BSD installed
just fine, except they don't like the Intel Centrino wifi chip. Stretch
lets you plugin a USB to supply the unfree software for the marvelous
Dell laptop. Oh well.
So PC-BSD boots just fine. When I hardwire to the router, I'm on the
web just fine. Then I gparted with the emergency boot part of CD boot
and resized the PC-BSD partition for room for a Stretch Linux partition.
Stretch installed fine. I was on the Web, and could apt-get all else I
wanted. The Stretch Grub was kept on a USB drive to not mess up the
PC-BSD Grub. So I rebooted into PC-BSD to see if I could add the
Stretch Linux partition.
The problem with PC-BSD is that grub did not see the Stretch Linux
partition! Well, maybe take the /etc/grub.d/10_linux grub file and
rename it 40_custom in the PC-BSD partition. Does it work?
No. I need to add some more info for the bugs.pcbsd.org people.
I had to reinstall PC-BSD after I installed Stretch too. Grub could not
find a tank:// pool to boot.
Installed PC-BSD 10.2 and Linux Debian Stretch.