Booting from USB on RPi3

[Mason Loring Bliss]

I'm struggling with how to boot FreeBSD 12 directly from a hard drive on an
RPi3b+, with no MMC card. It happens automatically with a Raspbian image, and
I got Devuan to boot this way by changing the right pointers in config.txt,
but I'm struggling to figure out how to do it on FreeBSD. I'm not sure what
dictates the boot behaviour.

No matter what I try, I seem to fail through to the system trying to netboot.

I read this thread:

    https://forums.freebsd.org/threads/booting-raspberry-pi-3-from-usb.71798/

...and that had me try changing fstab to point to the hard drive directly, but
that didn't work - the kernel hasn't loaded at that point - and there was the
notion of adding these to loader.conf:

    vfs.mountroot.timeout="15"
    vfs.mountfrom="ufs:/dev/da0s2a"

...but those seem not to be helping.

The bit that's frustrating is that clearly I'm starting the FreeBSD
bootloader, as seen here:

    https://wiki.freebsd.org/MasonLoringBliss?action=AttachFile&do=get&target=rpi-boot.jpg

How do I tell it to look at da0, either as a one-shot or persistently?
(Preferably both!) In exchange for help, I'll document the process, complete
with (better) screenshots, for the wiki.

Thanks!

-- 
Mason Loring Bliss            mason at blisses.org            http://blisses.org/  
The sand bats of Manark IV look like inanimate rock crystals until they attack.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://lists.freebsd.org/pipermail/freebsd-arm/attachments/20191023/b958fc74/attachment.sig>