Howto - Dual booting NetBSD from most Linux systems

[shep]

The following instructions resulted in a functional Crux Linux/NetBSD 9.2
x86_64 system.

Crux was installed first to the following 3 GPT partitions
1 - vfat (fat32) and tagged as System EFI boot
2 - Linux - swap
3 - Linux - ext4

I roughly split my hard drive in half with the first 3 partitions occupying
the first half. I was also generous with the 1st partition and gave it
1024Mb.

The disk layout should work with Debian/Crux/Slackware. The Fedora/RHEL
derivatives use logical-volume/xfs for default partitioning and I was unable
to get logical-volume/xfs to boot NetBSD. It did work in Fedora/RHEL
derivatives with standard gpt partitions and an ext4 /.
1 - /boot/efi 600 MiB
2 - / as ext4 and roughly 1/2 disk size - (swap+ 1 Gib)
3 - swap

From the working Linux install, use the partition manager to add
4 - NetBSD ufs2 (aka ffsV2)
5 - NetBSD swap

Then boot into the NetBSD install image select the / install destination as
dk3 (NetBSD numbers dk's from 0). When prompted to add NetBSD swap select yes.

Drop out of the install to the shell and mount another usb thumb drive.

mkdir /mnt2; mount -t msdos /dev/sd*e /mnt2

partitions are /dev/sd*e where * is the number assigned to your thumb drive.
cp /usr/mdec/bootx64.efi to the thumb drive. If you are installing to one of the
quirky laptops that uses bootia32.efi, copy that too.
While in the shell, you can check your partitioning by running

dkctl wd0 listwedges

.
NetBSD lables these as dk* wedges and you can have more than swap and /.
I also chose to format the ffsV2 partition although the installer, when you return to it,
should also format it.

newfs -O 2 dk3

As a side note, OpenBSD makes obtaining the *.EFI easy, it's at the top of the
download list:

[PARENTDIR] Parent Directory -
[ ] BOOTIA32.EFI 2021-09-30 13:01 124K
[ ] BOOTX64.EFI 2021-09-30 13:01 138K
[ ] BUILDINFO 2021-09-30 13:34 54
[ ] INSTALL.amd64 2021-09-30 13:33 43K
[ ] SHA256 2021-09-30 14:05 1.9K
[ ] SHA256.sig 2021-09-30 14:05 2.1K
[ ] base70.tgz 2021-09-30 13:26 303M
[ ] bsd 2021-09-30 13:25 21M
[ ] bsd.mp 2021-09-30 13:25 21M
[ ] bsd.rd 2021-09-30 13:34 4.0M

Be nice if NetBSD did the same.

"exit" the shell and return to the installer.

The installer has a quirk where it loops back to the initial installation step
when you select Install sets. The work around is to select
option c: Re-install sets ...

Re-install does not allow any post install configuration options or set
rc_configured=YES - your initial NetBSD boot will be in single user mode.

From single user mode mount the / partition(s):

mount -u /

and set the default terminal

TERM=vt220 ; export TERM

Edit /etc/rc.conf and change rc_configured to YES, set the hostname=
and setup your network.
Provisioned /etc/rc.conf

rc_configured=YES
hostname=
"Network per NetBSD guide"
wscons=YES

My keyboard and mouse gave me fits without wscons enabled.

Set root password

# passwd

Set user

useradd -m -G wheel -s /bin/sh "username"

Set user password

# passwd "username"

Set timezone

ln -sf /usr/share/zoneinfo/"Your Continent/Your zone" /etc/localtime

See the NetBSD guide for details and additional options
https://www.netbsd.org/docs/guide/en/

Boot back into linux and copy bootx64.efi (bootia32.efi) to /boot/efi/

Edit /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'NetBSD 9.2' {
         insmod part_gpt
         insmod search_fs_uuid
         insmod chain
         chainloader (hd0,gpt1)/bootx64.efi
}

Reconfigure grub with

grub-mkconfig -o /boot/grub/grub.cfg

or with Debian systems

update-grub

For Fedora/RHEL

grub2-mkconfig -o /boot/efi/EFI/rocky/grub.cfg

For Fedora/RHEL derivatives, adjust "rocky" in the output path for your variant.

[Head_on_a_Stick]

Great guide, thanks for this!

A few points, if I may:

Originally Posted by shep

cp /usr/mdec/bootx64.efi to the drive. If you are installing to one of the
quirky laptops that uses bootx32.efi, copy that too.

I think the 32-bit loader is supposed to be called bootia32.efi (at least according to the UEFI standard).

Originally Posted by shep

Edit /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry 'NetBSD 9.2' {
         insmod part_gpt
         insmod search_fs_uuid
         insmod chain
         chainloader (hd0,gpt1)/bootx64.efi
}

If multiple drives are connected then the (hd0,gpt1) identifier might not be consistently correct.

I prefer to use this (replace $uuid with the actual UUID of the EFI system partition):

menuentry 'NetBSD' {
   search --fs-uuid --set=root $uuid
   chainloader /bootx64.efi
}

I've never needed to manually load GRUB modules. YMMV.

HTH.

[shep]

Originally Posted by Head_on_a_Stick

I think the 32-bit loader is supposed to be called bootia32.efi (at least according to the UEFI standard).

Corrected - Thanks

Originally Posted by Head_on_a_Stick

I've never needed to manually load GRUB modules. YMMV.

In part, I'm compulsive and want to make sure they get loaded. In the context of a guide, I also lean towards showing what is going on under the hood.

[Sehnsucht94]

Amazing guide, thank you for having taken the time to write this up.