Dual boot Grub configuration for Fedora Cinnamon 37 and OpenBSD 7.2.

globetrotterdk · 12-01-2022, 05:23 AM

I have successfully installed Fedora Cinnamon 37 and OpenBSD on a single SSD (as that is all my computer supports). Unfortunately, I am having a difficult time with Grub's naming of hard disks and partitions. Here is what I know:
1) My SSD is at /dev/nvme0n1 in Fedora.
2) OpenBSD needs to be chain loaded for Grub to boot OpenBSD.
3) My OpenBSD 7.2 system is on the 6th. partition.
Is there anyone that can guide me with setting up Grub, so that I can boot my OpenBSD system?

colorpurple21859 · 12-01-2022, 06:44 AM

https://lowendunix.com/openbsd-multibooting-gpt/
grub counts disks from 0 and partitions from 1 if the efi partition is the first partition on the first drive it will be (hd0,1)

globetrotterdk · 12-01-2022, 09:26 AM

Quote:

Originally Posted by colorpurple21859

https://lowendunix.com/openbsd-multibooting-gpt/
grub counts disks from 0 and partitions from 1 if the efi partition is the first partition on the first drive it will be (hd0,1)

Thanks for the reply. Running grub> ls I get (hd0,gpt3), gpt4, gpt5, and gpt6. Exiting from the prompt boots me into OpenBSD. I think chain loading should take place at (hd0,gpt6), however the Fedora 37 system refuses to recognize anything due to the OpenBSD file system. I have also tried copying an OpenBSD BOOTX64.EFI file to /boot/efi/EFI/openbsd. I assume /boot is in / but it could be in the GPT partition as well. In other words, I am unsure where /boot resides.

So far, no luck from my end…

colorpurple21859 · 12-01-2022, 09:46 AM

boot into Fedora Cinnamon 37 open a terminal and post the output of the following:

Code:

df -h
sudo parted -l
sudo ls -R /boot/efi
sudo efibootmgr

globetrotterdk · 12-01-2022, 10:05 AM

Code:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        4.0M     0  4.0M   0% /dev
tmpfs           3.6G     0  3.6G   0% /dev/shm
tmpfs           1.5G  1.7M  1.5G   1% /run
/dev/nvme0n1p2  137G  7.1G  123G   6% /
tmpfs           3.6G   36K  3.6G   1% /tmp
/dev/nvme0n1p3  293G  569M  277G   1% /home
/dev/nvme0n1p1  489M   17M  473M   4% /boot/efi
tmpfs           727M   88K  727M   1% /run/user/1000

$ doas parted -l
Model: Samsung SSD 970 EVO Plus 1TB (nvme)
Disk /dev/nvme0n1: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name                  Flags
 1      1049kB  514MB   513MB   fat16           EFI System Partition  boot, esp
 2      514MB   151GB   150GB   ext4
 3      151GB   471GB   320GB   ext4
 4      471GB   473GB   2000MB  linux-swap(v1)                        swap
 5      473GB   523GB   50.0GB  ntfs                                  msftdata
 6      523GB   1000GB  478GB   ntfs


Model: Unknown (unknown)
Disk /dev/zram0: 7620MB
Sector size (logical/physical): 4096B/4096B
Partition Table: loop
Disk Flags: 

Number  Start  End     Size    File system     Flags
 1      0.00B  7620MB  7620MB  linux-swap(v1)

$ doas ls -R /boot/efi 
/boot/efi:
EFI  System  mach_kernel

/boot/efi/EFI:
BOOT  fedora  openbsd

/boot/efi/EFI/BOOT:
bootia32.efi  bootx64.efi  fbia32.efi  fbx64.efi

/boot/efi/EFI/fedora:
BOOTIA32.CSV  BOOTX64.CSV  gcdia32.efi	gcdx64.efi  grub.cfg  grubia32.efi  grubx64.efi  mmia32.efi  mmx64.efi	shim.efi  shimia32.efi	shimx64.efi

/boot/efi/EFI/openbsd:
bootx64_openbsd.efi

/boot/efi/System:
Library

/boot/efi/System/Library:
CoreServices

/boot/efi/System/Library/CoreServices:
SystemVersion.plist

$ doas efibootmgr
BootCurrent: 0001
Timeout: 0 seconds
BootOrder: 0001,0000,2001,2002,2003
Boot0000* Fedora	HD(1,GPT,c1af4596-58cd-4fe7-8eaa-91752cfbfde9,0x800,0xf4800)/File(\EFI\fedora\shim.efi) File(.䍒)
Boot0001* Fedora	HD(1,GPT,c1af4596-58cd-4fe7-8eaa-91752cfbfde9,0x800,0xf4800)/File(\EFI\fedora\shimx64.efi)
Boot2001* EFI USB Device	RC
Boot2002* EFI DVD/CDROM	RC
Boot2003* EFI Network	RC

To my knowledge, partition #6, which is where the OpenBSD system is installed, only is flagged in Linux as NTFS. I used the following procedure booting from a Parted Magic USB drive:
$ sudo gdisk /dev/nvme0n1
: t
: 6
: A600
: w
This was done to get OpenBSD to identify this as an OpenBSD partition during install, to allow the installer to autmatically partition this now former (?) NTFS partition.

globetrotterdk · 12-01-2022, 01:14 PM

Well, I thought that I had solved the problem, but of course, I didn't. However, the resulting errors were interesting, or at least I thought so. They can be seen here.

I have read warnings about not using something called osprober, but here the grub2-probe seems to be tied into Grub, without the option of it getting involved with the menu entry creation.

The Grub entry I created is as follows:
$ doas nano /etc/grub.d/40_custom

menuentry "OpenBSD" {
set root=(hd0,gpt1)
chainloader +1
}

colorpurple21859 · 12-01-2022, 02:00 PM

In uefi mode an efi file is chainloaded

Code:

menuentry "OpenBSD" {
set root=(hd0,gpt1)
chainloader /EFI/openbsd/bootx64_openbsd.efi
}

globetrotterdk · 12-02-2022, 12:27 AM

That seems to work, thanks. Is there a way that I can move the entry for OpenBSD further up the list? I am still getting errors in connection with updating Grub, so I’m not sure grub-customizer will work… Most importantly, I don’t want to break anything, now that the entry is working.

colorpurple21859 · 12-02-2022, 09:51 PM

Quote:

Is there a way that I can move the entry for OpenBSD further up the list?

The order of the grub entries is somewhat based on the numbering of the *.conf files in /etc/grub.d
copy /etc/grub.d/40_custom to /etc/grub.d/11_custom or /etc/grub.d/09_custom will move the entry just after or before the fedora entries.

yancek · 12-03-2022, 04:28 AM

The standard method of setting a menuentry in grub.cfg as the default is to edit the file /etc/default/grub and change the first line (GRUB_DEFAULT=0) from the default zero to whatever the number is for the BSD menuentry in grub.cfg. Grub count begins with zero. Renumbering the custom file should also work as you found.

Quote:

Most importantly, I don’t want to break anything, now that the entry is working.

Make a backup copy of the menuentries from grub.cfg since it is "mostly working" and put it somewhere else, /home/user directory.