Re: adding UEFI to NetBSD /boot/ [was Re: no HDMI on rpi4b NetBSD 10.1]

[Steve Rikli <sr%genyosha.net@localhost>]

On Thu, Jul 17, 2025 at 08:45:28AM +0200, Martin Husemann wrote:
> On Wed, Jul 16, 2025 at 11:06:10PM -0700, Steve Rikli wrote:
> > > If the RPi UEFI firmware conforms to the UEFI spec the only additional
> > > think you should need at this point is to copy /usr/mdec/bootaa64.efi
> > > from NetBSD to /boot/EFI/bootaa64.efi.
> 
> sorry, wrong path, your's is correct.
> 
> > Yeah, that matches my experience; I touched on this later in my (long!)
> > email message:
> > 
> > > I believe /boot/cmdline.txt is not required for UEFI -- my rpi4b boots
> > > NetBSD without it, so presumably the NetBSD "/" root filesystem location
> > > and kernel are specified elsewhere (/boot/EFI/BOOT/bootaa64.efi ?).
> 
> The file is the NetBSD UEFI bootloader, it has sane defaults and will
> find the kernel usually,

Good to know. RFE, it could be helpful to have a man page for
bootaa64.efi detailing some defaults and names and search paths and
such. I'd imagine something like this would be a per-architecture man
page, e.g. like evbarm/bootmini2440(8) et al.

The INSTALL guide mentions it, but mostly in the section "Upgrading a
previously-installed NetBSD System". Ie. not much context for initial
install or enhancing the firmware which comes with arm64.img; at least
INSTALL describes where the file can be ftp'd from, but not /usr/mdec/.

The evbarm wiki also talks about bootaa64.efi in "Updating the Firmware",
but the text is wrapped in /todo's. :-)  What's there is okay, but I can
see how it's kind of vague for someone unfamiliar with UEFI or generally
updating firmware like this. It makes more sense now that I've tried to
work through it, and read several port-arm threads etc.

> but it also reads hints where to find the kernel from /boot.cfg.

... but not for evbarm, yes? I.e. boot.cfg is for i386 and amd64 only?

> > I'd still like to understand where console is specified, though; and how
> > to change it. Aside from using the UEFI firmware manager, I mean, if it's
> > possible.
> 
> This is an implementation detail of the UEFI firmware you use (and where
> it stores its configuration).q
> 
> So best bet is to go to the setup menu via <ESC> and configure it there.

OK, that's what I suspected I'd end up with. It's not a showstopper by
any means, but it's kind of unfortunate, as IME NetBSD /boot.cfg is a
more capable and flexible mechanism.

Thanks,
sr.