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

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

On Tue, Jul 22, 2025 at 12:26:59PM +0200, Martin Husemann wrote:
> Yes, for arm boards it is basically 3 different things:
> 
>  - boards booting with FDT and u-boot (but no UEFI), mostly 32bit;
>    here you have to make sure the correct dtb file is loaded 
>    (names/defaults are in the  u-boot default environment), and the
>    right dtb file is available on the FAT partition of your boot medium
> 
>  - boards (mostly 64bit) that do not come with (usable) UEFI firmware.
>    Here you have to find the proper UEFI firmware and install it (e.g. in
>    flash memory)
> 
>  - boards that come with proper UEFI firmware right from the start, here
>    you can just boot the generic image. This part can be easily documented
>    (including boot.cfg) as it is the same on all arm boards
>
> For the first variant we provide various pre-configured images (derived
> from the generich image) on armbsd.org. If you have a board that should
> be in that list but isn't check if there is a pkgsrc sysutils/u-boot-*
> for your device, and try if that works. When it does, let us know so we
> can add it to the armbsd.org collection of images.
> 
> For the last variant there often is a EDK2 port and some of them are
> linked from the wiki (I use that e.g. on Quartz64 and Firefly P2S devices).
> This usually come with very good installation instructions.
> 
> For others you have to deal with the board specific UEFI firmware (like
> in the RPI cases) and "somehow" get that running first. Documenting this
> requires board+firmware specific knowledge.

I think a summary like this of the ~3 board types could be helpful in
the INSTALL guide, particularly if a couple common board/SoC examples
could be listed for each type.

The evbarm-aarch64 INSTALL guide almost doesn't mention UEFI; mostly
references to bootaa64.efi in "subdirectory structure" and "Upgrading a
previously-installed NetBSD System".

Whereas there's a section about "Installation for Armv7 and AArch64
devices with U-Boot". This looks like a common section across the
evbarm-* INSTALL guides.

I was thinking a section right after that e.g. "Installation for Armv7
and AArch64 devices with UEFI" and some of your notes would be a useful
starting point. That admittedly may not be applicable to some of the
other evbarm-* INSTALL guides.

The steps about dd'ing images and such are in-common, but the U-Boot
section mentions e.g. installing board-specific U-Boot, while INSTALL
has nothing comparable for UEFI.

> This is why knowledge is
> sparse. Things like "cmdline.txt" are specific to the RPI firmware
> and maybe even boot method used, I wouldn't be suprised if even on RPI
> the file would not be used at all when booting NetBSD via the UEFI
> boot loader.

Yes. IME rpi4b with UEFI notices the presence/absence of cmdline.txt
but NetBSD appears to not make use of it.

> Once UEFI runs, everything later is common again and should be well
> documented.

Agreed. Once I had NetBSD itself installed and running on the sysdisk,
post-install configuration for rpi4 was nearly identical to my other 
i386 and amd64 systems. Pleasantly so.  :-)

Cheers,
sr.