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FlexQ4

Member

Registered: 2017-02-19

Posts: 272

Multi-boot issue after installing Aquarius

Hello,
after installing Aquarius on an MBR-system on sda4 besides Windows (on sda1) and Q4OS-4 "Gemini" (on sda3):
In the boot-menu there are only the entrie for Q4os - os-prober states:

Found Debian GNU/Linux 11 (bullseye) on /dev/sda3

But what's missing/expected here would also be:

/dev/sda1:Windows 7:Windows:chain

Please, how can i get back Windows on my system??
Thank you!

Last edited by FlexQ4 (Today 11:11)

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,362

Website

Re: Multi-boot issue after installing Aquarius

Please run:
$ sudo os-prober
and post the output

FlexQ4

Member

Registered: 2017-02-19

Posts: 272

Re: Multi-boot issue after installing Aquarius

here it is:

[~\> sudo os-prober
[sudo] Passwort für me:
/dev/sda3:Debian GNU/Linux 11 (bullseye):Debian:linux

Weird enough: good (now old-old-old) Gemini still does find Windows:

[:~\> sudo os-prober
[sudo] Passwort für me:
/dev/sda1:Windows 7:Windows:chain
/dev/sda4:Debian GNU/Linux 12 (bookworm):Debian:linux

But for the moment (until the issue is claryfied) i won't run update-grub on Gemini...

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,362

Website

Re: Multi-boot issue after installing Aquarius

Would you check, whether there is another setting:
$ grep -R "GRUB_DISABLE_OS_PROBER" /etc/default/grub /etc/default/grub.d/ 2>/dev/null

FlexQ4

Member

Registered: 2017-02-19

Posts: 272

Re: Multi-boot issue after installing Aquarius

No, only the disabling of the "DISABLE_OS_PROBER":

# grep -R "GRUB_DISABLE_OS_PROBER" /etc/default/grub /etc/default/grub.d/ 2>/dev/null
/etc/default/grub:GRUB_DISABLE_OS_PROBER=false

/etc/default/grub.d is a directory which only contains an "empty" init-select.cfg file.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,362

Website

Re: Multi-boot issue after installing Aquarius

Two things decide this, please run on Aquarius:
$ [ -d /sys/firmware/efi ] && echo "UEFI boot" || echo "BIOS boot"
$ sudo os-prober
$ sudo grep -E "os-prober|50mounted-tests|20microsoft" /var/log/syslog | tail -30
$ sudo grub-mount /dev/sda1 /mnt && ls /mnt | head && sudo umount /mnt

Background: os-prober only reports Windows on a system booted in legacy BIOS mode -
its Windows detector exits immediately when /sys/firmware/efi exists, while Linux
systems are still listed. That alone produces exactly your output. If Aquarius
booted in UEFI mode and Gemini in BIOS mode, that is the answer, and a BIOS Windows
cannot be chainloaded from an EFI GRUB anyway - Windows then has to be started from
the firmware boot menu, or Q4OS's bootloader reinstalled in BIOS mode.

Otherwise the second possibility is that GRUB cannot read the NTFS partition:
os-prober mounts partitions only with grub-mount, and skips a partition silently if
that fails. The grub-mount line above shows it. In that case, mounting the Windows
partition before updating the menu works around it:
$ sudo mkdir -p /mnt/win && sudo mount -o ro /dev/sda1 /mnt/win
$ sudo update-grub
$ sudo umount /mnt/win

Your Gemini install is unaffected either way; running update-grub there is safe.

FlexQ4

Member

Registered: 2017-02-19

Posts: 272

Re: Multi-boot issue after installing Aquarius

It's only Lagacy/BIOS here on my pc. The output of the first block:

me@flex:~\> [ -d /sys/firmware/efi ] && echo "UEFI boot" || echo "BIOS boot"
BIOS boot

me@flex:~\> sudo os-prober
/dev/sda3:Debian GNU/Linux 11 (bullseye):Debian:linux

me@flex:~\> sudo grep -E "os-prober|50mounted-tests|20microsoft" /var/log/syslog | tail -30
2026-09-15T17:01:30.434456+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/05efi
2026-09-15T17:01:30.448226+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/10freedos
2026-09-15T17:01:30.461908+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/10qnx
2026-09-15T17:01:30.475361+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20macosx
2026-09-15T17:01:30.488883+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20microsoft
2026-09-15T17:01:30.497188+02:00 flex 20microsoft: debug: /dev/sda8 is a NTFS partition
2026-09-15T17:01:30.681517+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/30utility
2026-09-15T17:01:30.690619+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/40lsb
2026-09-15T17:01:30.696828+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/70hurd
2026-09-15T17:01:30.702876+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/80minix
2026-09-15T17:01:30.708620+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/83haiku
2026-09-15T17:01:30.717956+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/90linux-distro
2026-09-15T17:01:30.759998+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/90solaris
2026-09-15T17:01:30.763762+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/efi
2026-09-15T17:01:30.780375+02:00 flex os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda9
2026-09-15T17:01:31.069083+02:00 flex 50mounted-tests: debug: mounted using GRUB ntfs filesystem driver
2026-09-15T17:01:31.071423+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/05efi
2026-09-15T17:01:31.077153+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/10freedos
2026-09-15T17:01:31.082767+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/10qnx
2026-09-15T17:01:31.088325+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20macosx
2026-09-15T17:01:31.093991+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/20microsoft
2026-09-15T17:01:31.097497+02:00 flex 20microsoft: debug: /dev/sda9 is a NTFS partition
2026-09-15T17:01:31.226322+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/30utility
2026-09-15T17:01:31.231098+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/40lsb
2026-09-15T17:01:31.234279+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/70hurd
2026-09-15T17:01:31.237560+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/80minix
2026-09-15T17:01:31.240582+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/83haiku
2026-09-15T17:01:31.245326+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/90linux-distro
2026-09-15T17:01:31.268202+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/90solaris
2026-09-15T17:01:31.271715+02:00 flex 50mounted-tests: debug: running subtest /usr/lib/os-probes/mounted/efi

The second solution then seems to work::

me@flex:~\> sudo mkdir -p /mnt/win && sudo mount -o ro /dev/sda1 /mnt/win

me@flex:~\> sudo update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.1.0-53-amd64
Found initrd image: /boot/initrd.img-6.1.0-53-amd64
Found linux image: /boot/vmlinuz-6.1.0-44-amd64
Found initrd image: /boot/initrd.img-6.1.0-44-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 7 on /dev/sda1
/usr/sbin/grub-probe: error: unknown filesystem.
Found Debian GNU/Linux 11 (bullseye) on /dev/sda3
done

me@flex:~\> sudo umount /mnt/win
me@flex:~\> 

Please let me reboot...

Added later 30 min 16 s:
Many thanks for your support @q4osteam!

But it fails. The entry for Win7 in the boot menu is actually present, but when selecting it:

Settin partition type to 0x83
error: invalid signature

any key to continue

if i edit the entry, i can see the cause: the entry is far too less (as i saw it on a working system), even the partition uuid is missing!

Setparms 'Windows7 (on /dev/sda1)'
        insmod part_msdos
        parttool ${root} hidden-
        chainloader +1

This is disappointing, two steps at least back from Gemini tbh.

Should i try  sudo /media/me/<uuid of beloved Gemini partition>/usr/bin/os-prober ?

Edit: tried it - no success neither, only Gemini is found...

Last edited by FlexQ4 (Today 16:48)