so Raptor gave me access to a Talos II to do some work on FreeBSD/ppc64le.
first thing i noticed: the boot process is *very* unusual. it doesn't use the FreeBSD loader at all; instead it has a Linux-based firmware loader called Petitboot which can load and kexec() the FreeBSD kernel directly. however it needs a rather odd partition layout to do that:
# Device Mountpoint FStype Options Dump Pass#
/dev/nda0p2 / ufs rw 1 1
/dev/nda0p1 /boot msdosfs rw 2 2
i assume this is because Petitboot can't read FreeBSD UFS, so we need the kernel (which is in /boot/kernel) to be on FAT.
Raptor suggested we should make the loader kexec()able instead, which seems like a good idea, but from what i can tell this platform doesn't use OpenFirmware at all, and i'm not even sure we have a PowerNV-native loader.
(as you can tell, i know very little about either POWER or FreeBSD/powerpc, so this is going to be an interesting learning experience.)