Package: os-prober
Version: 1.80
Severity: normal
X-Debbugs-Cc: zalek.ste...@gmail.com
Dear Maintainer,
What led to the situation:
Debian Testing new linux kernel 5.18.0-1 and updated grub 2.06-3 installed via
apt package manager; the new linux kernel installation prompted the update-grub
function to run.
By default this new version of grub does not run the the os-prober package,
hence, the Windows 10 partition was not detected and was eliminated from the
grub.cfg list of bootable partitions.
What I did that was effective/ineffective (part 1):
- Added 'GRUB_DISABLE_OS_PROBER=false' to /etc/default/grub and ran 'sudo
update-grub', forcing os-prober/grub to search for Windows partition
- this resulted in the Windows 10 partition on this computer (box0) to be
recognized, but with errors >>
[incidentally, this exact procedure worked perfectly on my dual-boot Debian
Testing/Windows 10 laptop - no errors]
terminal output >>
---------------------------------------------------------------------------------------
zaleksf@box0:~$ sudo update-grub
[sudo] password for zaleksf:
Generating grub configuration file ...
Found background image: /usr/share/images/desktop-base/desktop-grub.png
Found linux image: /boot/vmlinuz-5.18.0-1-amd64
Found initrd image: /boot/initrd.img-5.18.0-1-amd64
Found linux image: /boot/vmlinuz-5.17.0-1-amd64
Found initrd image: /boot/initrd.img-5.17.0-1-amd64
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.
/usr/sbin/grub-probe: error: unknown filesystem.
Found Windows Boot Manager on /dev/sda1@/EFI/Microsoft/Boot/bootmgfw.efi
/usr/sbin/grub-probe: error: unknown filesystem.
Adding boot menu entry for UEFI Firmware Settings ...
done
---------------------------------------------------------------------------------------
Outcome:
Upon rebooting and seeing the main grub list screen, there were the usual
entries for booting to Debian, Windows, etc. However, upon selecting the
Windows boot entry, I received an error indicating
'/EFI/Microsoft/Boot/bootmgfw.efi does not exist'
This was false, as I could find this file from both the Debian OS and Windows
OS file manager, and I could boot directly into Windows 10 from the BIOS using
the 'Enter/F12' key combination to bring up a list of boot partition choices
(which did show both Debian and Windows as options).
I investigated grub.cfg file and found that the 30_os-prober section for
Windows to be significantly truncated from its usual entry (and other Linux
kernel entries) >>
### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/sda1)' --class windows --class os
$menuentry_id_option 'osprober-efi-/dev/sda1' {
insmod part_gpt
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/30_os-prober ###
What I did that was effective/ineffective (part 2):
Since my laptop (box1) also is dual-boot Debian Testing/Windows 10 with a
virtually identical set-up, I tried an experiment of copying its complete (and
functioning) 30_os-prober section to grub.cfg on this misbehaving desktop
system (box0). I tweaked this section (using logic) to point to the proper
Windows partition, etc. (since I really have no experience with grub at all).
Manually changed section 30_os-prober to this >>
### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/sda1)' --class windows --class os
$menuentry_id_option 'osprober-efi-/dev/sda1' {
insmod part_gpt
insmod fat
set root='hd0,gpt1'
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt1 --hint-
efi=hd0,gpt1 --hint-baremetal=ahci0,gpt1 82CB-1126
else
search --no-floppy --fs-uuid --set=root 54C7-5867
fi
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
### END /etc/grub.d/30_os-prober ###
Saved grub.cfg, rebooted machine and selected Windows entry from grub.
Outcome:
Can boot into the Windows 10 partition perfectly, just as before. All grub list
entries work correctly.
If I run 'update-grub' again, the grub-probe error is indicated in the
terminal, and the truncated/broken section 30_os-prober returns to
/boot/grub/grub.cfg
My machine (and Windows and Debian) works just fine. This machine has been
dual-boot Debian Testing/Windows 10 for the last 5 years and has never
experienced this issue before this version of grub/os-prober was introduced.
My recommendation is to look into why the os-prober successfully recognizes a
dual-boot Windows partition for some machines and not others. Please let me
know if I can send additional files to support troubleshooting and/or
development.
Best regards, SZ
-- System Information:
Debian Release: bookworm/sid
APT prefers testing
APT policy: (800, 'testing'), (500, 'unstable'), (200, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 5.18.0-1-amd64 (SMP w/16 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages os-prober depends on:
ii grub-common 2.06-3
ii libc6 2.33-7
ii mount 2.38-4
os-prober recommends no packages.
os-prober suggests no packages.
-- no debconf information
