Arch Linux

x_driver

Member

Registered: 2019-02-05

Posts: 14

[SOLVED] GRUB config file not showing another Arch OS

I have 2 Arch installations, one on partitions 1, 2, 3 and another on 4, 5, 6.  I followed the wiki on using os-prober after mounting the other installations mount point.  Running grub-mkconfig says that an entry will be added for the additional installation but it doesn't appear in the file.  What am I missing?

[htpc@htpc ~]$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0   3.6T  0 disk 
sdb           8:16   0   3.6T  0 disk 
sdc           8:32   0   1.4T  0 disk 
└─sdc1        8:33   0   1.4T  0 part 
sdd           8:48   1   7.2G  0 disk 
├─sdd1        8:49   1   776M  0 part 
└─sdd2        8:50   1    74M  0 part 
nvme0n1     259:0    0 931.5G  0 disk 
├─nvme0n1p1 259:1    0   9.8G  0 part 
├─nvme0n1p2 259:2    0   7.8G  0 part 
├─nvme0n1p3 259:3    0 390.6G  0 part 
├─nvme0n1p4 259:4    0   9.8G  0 part /boot
├─nvme0n1p5 259:5    0   7.8G  0 part [SWAP]
└─nvme0n1p6 259:6    0 505.7G  0 part /

[htpc@htpc ~]$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0   3.6T  0 disk 
sdb           8:16   0   3.6T  0 disk 
sdc           8:32   0   1.4T  0 disk 
└─sdc1        8:33   0   1.4T  0 part 
sdd           8:48   1   7.2G  0 disk 
├─sdd1        8:49   1   776M  0 part 
└─sdd2        8:50   1    74M  0 part 
nvme0n1     259:0    0 931.5G  0 disk 
├─nvme0n1p1 259:1    0   9.8G  0 part 
├─nvme0n1p2 259:2    0   7.8G  0 part 
├─nvme0n1p3 259:3    0 390.6G  0 part /mnt
├─nvme0n1p4 259:4    0   9.8G  0 part /boot
├─nvme0n1p5 259:5    0   7.8G  0 part [SWAP]
└─nvme0n1p6 259:6    0 505.7G  0 part /

[htpc@htpc ~]$ sudo os-prober
/dev/nvme0n1p3:Arch Linux:Arch:linux

[htpc@htpc ~]$ sudo grub-mkconfig -o /boot/grub/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-linux
Found initrd image: /boot/intel-ucode.img /boot/initramfs-linux.img
Found fallback initrd image(s) in /boot:  intel-ucode.img initramfs-linux-fallback.img
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Arch Linux on /dev/nvme0n1p3
Adding boot menu entry for UEFI Firmware Settings ...
done

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
insmod part_gpt
insmod part_msdos
if [ -s $prefix/grubenv ]; then
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="0"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

if [ x$feature_default_font_path = xy ] ; then
   font=unicode
else
insmod part_gpt
insmod btrfs
search --no-floppy --fs-uuid --set=root 9f701099-ce4a-4b3a-af94-0b1034628658
    font="/usr/share/grub/unicode.pf2"
fi

if loadfont $font ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_US
  insmod gettext
fi
terminal_input console
terminal_output gfxterm
if [ x$feature_timeout_style = xy ] ; then
  set timeout_style=menu
  set timeout=5
# Fallback normal timeout code in case the timeout_style feature is
# unavailable.
else
  set timeout=5
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Arch Linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-9f701099-ce4a-4b3a-af94-0b1034628658' {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_gpt
	insmod fat
	search --no-floppy --fs-uuid --set=root 66C9-304B
	echo	'Loading Linux linux ...'
	linux	/vmlinuz-linux root=UUID=9f701099-ce4a-4b3a-af94-0b1034628658 rw  loglevel=3 quiet
	echo	'Loading initial ramdisk ...'
	initrd	/intel-ucode.img /initramfs-linux.img
}
submenu 'Advanced options for Arch Linux' $menuentry_id_option 'gnulinux-advanced-9f701099-ce4a-4b3a-af94-0b1034628658' {
	menuentry 'Arch Linux, with Linux linux' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-linux-advanced-9f701099-ce4a-4b3a-af94-0b1034628658' {
		load_video
		set gfxpayload=keep
		insmod gzio
		insmod part_gpt
		insmod fat
		search --no-floppy --fs-uuid --set=root 66C9-304B
		echo	'Loading Linux linux ...'
		linux	/vmlinuz-linux root=UUID=9f701099-ce4a-4b3a-af94-0b1034628658 rw  loglevel=3 quiet
		echo	'Loading initial ramdisk ...'
		initrd	/intel-ucode.img /initramfs-linux.img
	}
	menuentry 'Arch Linux, with Linux linux (fallback initramfs)' --class arch --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-linux-fallback-9f701099-ce4a-4b3a-af94-0b1034628658' {
		load_video
		set gfxpayload=keep
		insmod gzio
		insmod part_gpt
		insmod fat
		search --no-floppy --fs-uuid --set=root 66C9-304B
		echo	'Loading Linux linux ...'
		linux	/vmlinuz-linux root=UUID=9f701099-ce4a-4b3a-af94-0b1034628658 rw  loglevel=3 quiet
		echo	'Loading initial ramdisk ...'
		initrd	/intel-ucode.img /initramfs-linux-fallback.img
	}
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###

### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
	fwsetup
}
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/40_custom ###
# 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.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg
fi
### END /etc/grub.d/41_custom ###

Last edited by x_driver (2021-12-22 00:02:52)

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 8,811

Website

Re: [SOLVED] GRUB config file not showing another Arch OS

Is the other Arch system's /boot directory mounted when os-prober runs? It will need to be for the kernel & intramfs images to be discoverable.

---

Jin, Jîyan, Azadî

x_driver

Member

Registered: 2019-02-05

Posts: 14

Re: [SOLVED] GRUB config file not showing another Arch OS

A few attempts earlier I was mounting the other installs partition 1 into /mnt/boot. I'll try that again and report back.

When the other install was showing on Grub and I would try to boot it I kept getting the "you need to load the kernel first" message. Tried chrooting from the live install to reinstall Linux, etc, etc, but only the OS on 4, 5, and 6 boots.

x_driver

Member

Registered: 2019-02-05

Posts: 14

Re: [SOLVED] GRUB config file not showing another Arch OS

Head,

I mounted the /boot partition like you suggested, ran the os-prober, ran grub-mkconfig, rebooted and the grub menu showed the appropriate entries.  I must be doing something wrong because now the OS on partitions 4, 5, and 6 can't find the kernel.  So i'm using the Arch install from post 1 that I couldn't boot and the one that was working won't boot.  There has got to be some simple step that I'm omitting.

[htpc@htpc ~]$ lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0   3.6T  0 disk 
sdb           8:16   0   3.6T  0 disk 
sdc           8:32   0   1.4T  0 disk 
└─sdc1        8:33   0   1.4T  0 part 
sdd           8:48   1   7.2G  0 disk 
├─sdd1        8:49   1   776M  0 part /run/media/htpc/ARCH_202112
└─sdd2        8:50   1    74M  0 part 
nvme0n1     259:0    0 931.5G  0 disk 
├─nvme0n1p1 259:1    0   9.8G  0 part /boot
├─nvme0n1p2 259:2    0   7.8G  0 part [SWAP]
├─nvme0n1p3 259:3    0 390.6G  0 part /
├─nvme0n1p4 259:4    0   9.8G  0 part 
├─nvme0n1p5 259:5    0   7.8G  0 part 
└─nvme0n1p6 259:6    0 505.7G  0 part 

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 8,811

Website

Re: [SOLVED] GRUB config file not showing another Arch OS

Perhaps the identical kernel & initramfs image names are confusing grub-mkconfig & os-prober.

Try a manual entry for the "other" Arch system. Something like this in the /dev/nvme0n1p{1,2,3} system should work:

menuentry 'Other Arch' {
   search --fs-uuid --set=root $uuid_nvme0n1p4
   linux /vmlinuz-linux root=UUID=$uuid_nvme0n1p6 rw quiet
   initrd /intel-ucode.img /initramfs-linux.img
}

Replace $uuid_nvme0n1p4 & $uuid_nvme0n1p6 with the actual UUIDs for those partitions, add the stanza to the end of /etc/grub.d/40_custom and re-generate grub.cfg afterwards.

---

Jin, Jîyan, Azadî

x_driver

Member

Registered: 2019-02-05

Posts: 14

Re: [SOLVED] GRUB config file not showing another Arch OS

Head,

Thanks for the help.  I followed your steps verbatim and the problem persisted.  Then I followed your steps again except for the part where you said to "re-generate grub.cfg" and I'm able to boot into both OS's.

2 questions.

1.  Does it matter that the /boot/grub/grub.cfg files are different in each OS?
2.  Do I need to be concerned when running a full system update via pacman?

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 8,811

Website

Re: [SOLVED] GRUB config file not showing another Arch OS

I followed your steps verbatim and the problem persisted.  Then I followed your steps again except for the part where you said to "re-generate grub.cfg" and I'm able to boot into both OS's.

To which file did you add my posted code block? From your description it sounds like you edited /boot/grub/grub.cfg directly, which isn't what I suggested.

The "correct" approach is to add the text to the end of the file at /etc/grub.d/40_custom, which would then be added to grub.cfg by grub-mkconfig. It's not critical though because Arch users don't need to regenerate grub.cfg after kernel updates (the kernel image name is non-versioned, unlike most other distributions) but adding it to grub.cfg directly would cause it to be lost if grub.cfg is ever regenerated, which is what you have described.

Does it matter that the /boot/grub/grub.cfg files are different in each OS?

Not really.

An alternative approach would be to use grub.cfg in the "other" Arch system to show a menu, like this:

menuentry 'Other Arch' {
   search --fs-uuid --set=root $uuid_nvme0n1p4
   configfile /grub/grub.cfg
}

But then you would have to go through two menus to boot the second system.

Do I need to be concerned when running a full system update via pacman?

No, the kernel & initramfs images in Arch are non-versioned so the menuentry should remain functional even after kernel updates. The same applies to the µcode package.

---

Jin, Jîyan, Azadî

x_driver

Member

Registered: 2019-02-05

Posts: 14

Re: [SOLVED] GRUB config file not showing another Arch OS

Head,

Thanks again.

To which file did you add my posted code block? From your description it sounds like you edited /boot/grub/grub.cfg directly, which isn't what I suggested.

Yeah, I edited this file.  I see the /etc/grub.d/custom_40 that I should be editing.  I'll make the appropriate changes to make it correct.