Netboot a NetBSD kernel then use a local filesystem?

[Tom Lane <tgl%sss.pgh.pa.us@localhost>]

The available documentation seems to cover only the case of netbooting
with storage on NFS.  What I'd like to do is load the kernel from a
netboot server but then run with local storage.  The scenario is
that I've acquired a USB PCI card[1] that seems to work fine in my
hppa C360, and I can run NetBSD on a USB disk connected to that card;
but of course, HP's boot ROM has no idea what to do with that USB card
so there's zero hope of booting the kernel off the USB disk.

As things stand, after netbooting the kernel it tries and fails to find
an NFS filesystem (because I've not set up the relevant DHCP/BOOTP
parameters) and then asks me what to do.  If I type in "sd2" as the
root device, and then default a few more questions, I'm off and running.
But of course this prevents unattended boot or reboot, so I'd sure like
to get rid of the requirement for manual input.

I poked around in the kernel sources and I think I see where I could
hack the startup code, but I didn't find any provision for a supported
means of doing what I want.  Have I missed a way to configure things
like that?

			regards, tom lane

[1] https://www.amazon.com/dp/B002VY53ZK?psc=1&ref=ppx_yo2ov_dt_b_product_details