Re: dual boot installation with UEFI

["DTB" <trinity@tebibyte.media>]

On Fri Sep 25, 2026 at 7:06 PM MDT, Jeff wrote:
> Hi, folks,
>
> I wish to install NetBSD into the unused space (or I can pre-format
> it, if that would help) on a drive which already has a UEFI partition
> and a partition on which Gentoo is installed, and I want to keep Gentoo
> intact. I cannot find any instructions or tutorials regarding installing
> on a disk that has another OS on it...

I did this. I created 2 new GPT partitions, swap and /, which were
respectively 4GB and however much space was left after that, and they
worked fine with the installer. If I recall correctly, the installer
will install NetBSD into the ESP at ESP:/NetBSD/, but I installed rEFInd
to triple boot with the existing Windows 10 and Linux Mint partitions. I
did have trouble with booting NetBSD because my boot.cfg (which should
be at ESP:/NetBSD/) was improperly formatted, and I described my
configuration at the time here:
<https://mail-index.netbsd.org/netbsd-users/2026/08/02/msg034580.html>
and figured it out here:
<https://mail-index.netbsd.org/netbsd-users/2026/08/06/msg034603.html>

> ....and all of my attempts have failed when I get to the point of
> accepting the disk layout. It quickly fails with a complaint about not
> being able to access /dev/dk* (and I'm trying to install on nvme).

I didn't encounter this problem. It makes sense that dk(4) would be
having those issues because the system uses (or at least did for me,
using a SATA hard drive) /dev/dk* nodes for GPT partitions. In the
previous hyperlinked e-mail thread RVP does a great job of briefly
explaining how this works.

Someone else might be able to intuit what you are missing from this
information alone but I wonder if you could provide a more detailed
recollection of the dk(4) complaint.

> Is there a tutorial or FAQ somewhere that I'm not finding, or does
> anyone have any tips for how I might proceed?

<https://bentsukun.ch/posts/netbsd-wedge-boot/> was a great resource for
me for understanding NetBSD and UEFI, but going so far as in-kernel boot
configuration was unnecessary in my case.

Sorry I can't help with your problem. I hope this helps once you make it
past this initial hurdle. Happy hacking.

<3 :3 -3