In the meantime, you are free to look at FreeBSD/powerpc64 which already works on all powerpc64 (including POWER9).
There’s a lot of work going on in FreeBSD/ppc land.
I don’t think I’ve ever had the FreeBSD bootloader work on pSeries…
Not many people use those, most FreeBSD/powerpc64 use G5 and there’s more and more people using Raptor machines. It’s been also confirmed that FreeBSD works on Amiga X5000, Tyan POWER8 and IBM POWER9 machines.
Probably not those, because those are PowerVM (pSeries), not PowerNV…
Not really. Some are PowerVM, but some are PowerNV. It depends whether they are OpenPOWER machines or not. OpenPOWER machines all (including Raptor machines) use OpenPOWER firmware (Hostboot, Petitboot etc.). IBM machines that are not OpenPOWER use IBM’s proprietary firmware.
By IBM POWER9 in my previous post I meant IBM’s OpenPOWER machines (they are available at OSU for FOSS developers). I don’t have any knowledge about whether PowerVM work now, probably no one tried FreeBSD on PowerVM with POWER9.