I had a PC with Kubuntu 20.04 then added a second drive and installed
Almalinux on it. Then did the grub update from Alma and it added Ubuntu
to boot menu. So boot back into Ubuntu and tried to do the reciprocal
deed. But grub-update did not add Alma linux.
Both fdisk and lsblk see the other disk drive from Ubuntu, but grub
updater apparently does not digest it.

On 6/11/22 19:39, Karen wrote:
> I had a PC with Kubuntu 20.04 then added a second drive and installed
> Almalinux on it. Then did the grub update from Alma and it added Ubuntu
> to boot menu. So boot back into Ubuntu and tried to do the reciprocal
> deed. But grub-update did not add Alma linux.

Is the PC using MBR or GPT?
Did you install Alma's grub to a separate disk/partition or to the MBR?
Do you really have 2 Grub's installed to separate partitions?

Most times you only have one grub installed. So maybe it's your Alma's
grub that's installed and controlling your boot loading. So when you
boot to Ubuntu, the grub-update does see Alma but you don't see your
Ubuntu's grub when you reboot because you're seeing only Alma's grub.

You'd need to chain load your grub's if you really want to use both. Or
maybe os-prober is disabled in your ubuntu's grub. Not positive because
you weren't really clear about where/how you installed either grub.

On 6/12/2022 2:22 AM, stepore wrote:
> On 6/11/22 19:39, Karen wrote:
>> I had a PC with Kubuntu 20.04 then added a second drive and installed
>> Almalinux on it. Then did the grub update from Alma and it added Ubuntu
>> to boot menu. So boot back into Ubuntu and tried to do the reciprocal
>> deed. But grub-update did not add Alma linux.
>
> Is the PC using MBR or GPT?
> Did you install Alma's grub to a separate disk/partition or to the MBR?
> Do you really have 2 Grub's installed to separate partitions?
>
> Most times you only have one grub installed. So maybe it's your Alma's grub
> that's installed and controlling your boot loading. So when you boot to Ubuntu,
> the grub-update does see Alma but you don't see your Ubuntu's grub when you reboot because you're seeing only Alma's grub.
>
> You'd need to chain load your grub's if you really want to use both. Or maybe
> os-prober is disabled in your ubuntu's grub. Not positive because you weren't
> really clear about where/how you installed either grub.

Poor os-prober.

Kicked around like a football.

I'm working on Gentoo right now, and can't get any of the
other Linux on the disk to get picked up either. There's
a cryptic message about "mounts", as if mounting the alternate
OSes would help, but that did not help at all.

So now I'm trapped inside Gentoo :-) Cool beanz.

There was a time when all you had to do, was install
the package for os-prober, to get it to work. But not
any more. Now they're laying spike belts in the road
and so on.

Maybe I need my copy of BootMagic from the year 2000.

*******

"One workaround (for now) is to add

GRUB_DISABLE_OS_PROBER=false

to the file

/etc/default/grub
"

sudo gedit /etc/default/grub # or similar

But on Gentoo, that directive was just ignored.

If you can't find os-prober, in the old days it was

sudo apt install os-prober

which at the time was only a 23KB file.

Paul

Paul wrote:
> On 6/12/2022 2:22 AM, stepore wrote:
>> On 6/11/22 19:39, Karen wrote:
>>> I had a PC with Kubuntu 20.04 then added a second drive and installed
>>> Almalinux on it. Then did the grub update from Alma and it added Ubuntu
>>> to boot menu. So boot back into Ubuntu and tried to do the reciprocal
>>> deed. But grub-update did not add Alma linux.
>>
>> Is the PC using MBR or GPT?
>> Did you install Alma's grub to a separate disk/partition or to the MBR?
>> Do you really have 2 Grub's installed to separate partitions?
>>
>> Most times you only have one grub installed. So maybe it's your Alma's
>> grub that's installed and controlling your boot loading. So when you
>> boot to Ubuntu, the grub-update does see Alma but you don't see your
>> Ubuntu's grub when you reboot because you're seeing only Alma's grub.
>>
>> You'd need to chain load your grub's if you really want to use both.
>> Or maybe os-prober is disabled in your ubuntu's grub. Not positive
>> because you weren't really clear about where/how you installed either
>> grub.
>
> Poor os-prober.
>
> Kicked around like a football.
>
> I'm working on Gentoo right now, and can't get any of the
> other Linux on the disk to get picked up either. There's
> a cryptic message about "mounts", as if mounting the alternate
> OSes would help, but that did not help at all.
>
> So now I'm trapped inside Gentoo :-) Cool beanz.
>
> There was a time when all you had to do, was install
> the package for os-prober, to get it to work. But not
> any more. Now they're laying spike belts in the road
> and so on.
>
> Maybe I need my copy of BootMagic from the year 2000.
>
> *******
>
>    "One workaround (for now) is to add
>
>        GRUB_DISABLE_OS_PROBER=false
>
>    to the file
>
>        /etc/default/grub
>    "
>
> sudo gedit /etc/default/grub         # or similar
>
> But on Gentoo, that directive was just ignored.
>
> If you can't find os-prober, in the old days it was
>
>    sudo apt install os-prober
>
> which at the time was only a 23KB file.
>
>    Paul

GNU GRUB - New in 2.06:
https://git.savannah.gnu.org/cgit/grub.git/tree/NEWS?h=grub-2.06

* Disable the os-prober by default.

Ubuntu 22.04 Release Notes
https://discourse.ubuntu.com/t/jammy-jellyfish-release-notes/24668

<quote>

UEFI and BIOS boot

Other operating systems are not displayed in the boot menu anymore,
unless Ubuntu has been installed alongside another operating system.
Once all other operating systems are removed from the machine, detection
of other operating systems is disabled, and to re-enable if after
installing another OS, you will have to delete /boot/grub/grub.cfg and
immediately run update-grub again.

<unquote>

On 6/12/2022 9:41 AM, Andrei Z. wrote:

>
> GNU GRUB - New in 2.06:
> https://git.savannah.gnu.org/cgit/grub.git/tree/NEWS?h=grub-2.06
>
> * Disable the os-prober by default.
>
> Ubuntu 22.04 Release Notes
> https://discourse.ubuntu.com/t/jammy-jellyfish-release-notes/24668
>
> <quote>
>
> UEFI and BIOS boot
>
> Other operating systems are not displayed in the boot menu anymore, unless Ubuntu has been installed alongside another operating system. Once all other operating systems are removed from the machine, detection of other operating systems is disabled, and to re-enable if after installing another OS, you will have to delete /boot/grub/grub.cfg and immediately run update-grub again.
>
> <unquote>

Before trying Gentoo, I had:

+-----+--------+----------+------------+---------+
| MBR | Swap | Ubuntu | LinuxMint | Zorin |
+-----+--------+----------+------------+---------+

Boot Menu shows:

Zorin
Ubuntu
LinuxMint

Deleted Zorin (as Firefox source of V75 delivered as source archive
and Firefox deb of V101 delivered, mismatch of goods). Ubuntu
only delivered Firefox as Snap. LinuxMint deal with Mozilla
means no source archive matching delivered Firefox V101.

Installed Gentoo (no boot partition, just using /boot on /)

+-----+--------+----------+------------+---------+
| MBR | Swap | Ubuntu | LinuxMint | Gentoo |
+-----+--------+----------+------------+---------+

Boot Menu shows:

Gentoo # And no other Linux OSes are picked up

Even with /etc/fstab entries causing Ubuntu and LinuxMint
partitions to be mounted while Gentoo is running, no difference
in symptoms. Using GRUB_DISABLE_OS_PROBER=false
did nothing. There's a spike belt, a barricade of some sort,
still in there... And you know the staff who do these
things, snicker like Beavis and Butthead while doing
breakage like this.

The thing is, even if you "fix" it manually, every time a
kernel gets patched, GRUB will get updated again and
whatever you did will get broken. That's why this matters.
It's not fixing it I care about. It's the user-abrasive
automation that will fuck it all up again, that I care about!

Paul

On 6/12/22 11:34, Paul wrote:
> On 6/12/2022 9:41 AM, Andrei Z. wrote:
>
>>
>> GNU GRUB - New in 2.06:
>> https://git.savannah.gnu.org/cgit/grub.git/tree/NEWS?h=grub-2.06
>>
>> * Disable the os-prober by default.
>>
>> Ubuntu 22.04 Release Notes
>> https://discourse.ubuntu.com/t/jammy-jellyfish-release-notes/24668
>>
>> <quote>
>>
>> UEFI and BIOS boot
>>
>> Other operating systems are not displayed in the boot menu anymore,
>> unless Ubuntu has been installed alongside another operating system.
>> Once all other operating systems are removed from the machine,
>> detection of other operating systems is disabled, and to re-enable if
>> after installing another OS, you will have to delete
>> /boot/grub/grub.cfg and immediately run update-grub again.
>>
>> <unquote>
>
> Before trying Gentoo, I had:
>
> +-----+--------+----------+------------+---------+
> | MBR |  Swap  |  Ubuntu  |  LinuxMint |  Zorin  |
> +-----+--------+----------+------------+---------+
>
> Boot Menu shows:
>
>     Zorin
>     Ubuntu
>     LinuxMint
>
> Deleted Zorin (as Firefox source of V75 delivered as source archive
> and Firefox deb of V101 delivered, mismatch of goods). Ubuntu
> only delivered Firefox as Snap. LinuxMint deal with Mozilla
> means no source archive matching delivered Firefox V101.
>
> Installed Gentoo (no boot partition, just using /boot on /)
>
> +-----+--------+----------+------------+---------+
> | MBR |  Swap  |  Ubuntu  |  LinuxMint |  Gentoo |
> +-----+--------+----------+------------+---------+
>
> Boot Menu shows:
>
>    Gentoo     # And no other Linux OSes are picked up
>
> Even with /etc/fstab entries causing Ubuntu and LinuxMint
> partitions to be mounted while Gentoo is running, no difference
> in symptoms. Using GRUB_DISABLE_OS_PROBER=false
> did nothing. There's a spike belt, a barricade of some sort,
> still in there...  And you know the staff who do these
> things, snicker like Beavis and Butthead while doing
> breakage like this.
>
> The thing is, even if you "fix" it manually, every time a
> kernel gets patched, GRUB will get updated again and
> whatever you did will get broken. That's why this matters.
> It's not fixing it I care about. It's the user-abrasive
> automation that will fuck it all up again, that I care about!
>
>    Paul
>

Many Linux distributions ignore other installed OSes. I used
to use the multiple partition capability of UEFI to have many partitions
and installed several distributions to the system and the GRUB lists
almost always got messed up. I switched to running them under Virtual
Box and other such emulators could be used.

bliss - brought to you by the power and ease of PCLinuxOS,
the Perfect Computer Linux Operating System,
and a minor case of hypergraphia

--
bliss dash SF 4 ever at dslextreme dot com

Paul wrote:
> On 6/12/2022 9:41 AM, Andrei Z. wrote:
>
>>
>> GNU GRUB - New in 2.06:
>> https://git.savannah.gnu.org/cgit/grub.git/tree/NEWS?h=grub-2.06
>>
>> * Disable the os-prober by default.
>>
>> Ubuntu 22.04 Release Notes
>> https://discourse.ubuntu.com/t/jammy-jellyfish-release-notes/24668
>>
>> <quote>
>>
>> UEFI and BIOS boot
>>
>> Other operating systems are not displayed in the boot menu anymore,
>> unless Ubuntu has been installed alongside another operating system.
>> Once all other operating systems are removed from the machine,
>> detection of other operating systems is disabled, and to re-enable if
>> after installing another OS, you will have to delete
>> /boot/grub/grub.cfg and immediately run update-grub again.
>>
>> <unquote>
>
> Before trying Gentoo, I had:
>
> +-----+--------+----------+------------+---------+
> | MBR |  Swap  |  Ubuntu  |  LinuxMint |  Zorin  |
> +-----+--------+----------+------------+---------+
>
> Boot Menu shows:
>
>     Zorin
>     Ubuntu
>     LinuxMint
>
> Deleted Zorin (as Firefox source of V75 delivered as source archive
> and Firefox deb of V101 delivered, mismatch of goods). Ubuntu
> only delivered Firefox as Snap. LinuxMint deal with Mozilla
> means no source archive matching delivered Firefox V101.
>
> Installed Gentoo (no boot partition, just using /boot on /)
>
> +-----+--------+----------+------------+---------+
> | MBR |  Swap  |  Ubuntu  |  LinuxMint |  Gentoo |
> +-----+--------+----------+------------+---------+
>
> Boot Menu shows:
>
>    Gentoo     # And no other Linux OSes are picked up
>
> Even with /etc/fstab entries causing Ubuntu and LinuxMint
> partitions to be mounted while Gentoo is running, no difference
> in symptoms. Using GRUB_DISABLE_OS_PROBER=false
> did nothing. There's a spike belt, a barricade of some sort,
> still in there...  And you know the staff who do these
> things, snicker like Beavis and Butthead while doing
> breakage like this.
>
> The thing is, even if you "fix" it manually, every time a
> kernel gets patched, GRUB will get updated again and
> whatever you did will get broken. That's why this matters.
> It's not fixing it I care about. It's the user-abrasive
> automation that will fuck it all up again, that I care about!
>
>    Paul
>
GNU GRUB Manual 2.06
https://www.gnu.org/software/grub/manual/grub/grub.html#Simple-configuration

<quote>
‘GRUB_DISABLE_OS_PROBER’

The grub-mkconfig has a feature to use the external os-prober program to
discover other operating systems installed on the same machine and
generate appropriate menu entries for them. It is disabled by default
since automatic and silent execution of os-prober, and creating boot
entries based on that data, is a potential attack vector. Set this
option to ‘false’ to enable this feature in the grub-mkconfig command.
<unquote>

It looks like they want us to use UEFI boot.

Booting a UEFI machine normally - Debian Wiki
https://wiki.debian.org/UEFI#Booting_a_UEFI_machine_normally

"Regular UEFI boot has several lists of possible boot entries, stored in
UEFI config variables (normally in NVRAM), and boot order config
variables stored alongside them. It allows for many different boot
options, and a properly-defined fallback order. In many cases, you can
even list and choose which OS / boot loader to use from the system boot
menu (similar to the boot device menu implemented in many BIOSes).
Unfortunately, a lot of PC UEFI implementations have got this wrong and
so don't work properly."

On 6/12/2022 3:57 PM, Bobbie Sellers wrote:
> On 6/12/22 11:34, Paul wrote:
>> On 6/12/2022 9:41 AM, Andrei Z. wrote:
>>
>>>
>>> GNU GRUB - New in 2.06:
>>> https://git.savannah.gnu.org/cgit/grub.git/tree/NEWS?h=grub-2.06
>>>
>>> * Disable the os-prober by default.
>>>
>>> Ubuntu 22.04 Release Notes
>>> https://discourse.ubuntu.com/t/jammy-jellyfish-release-notes/24668
>>>
>>> <quote>
>>>
>>> UEFI and BIOS boot
>>>
>>> Other operating systems are not displayed in the boot menu anymore, unless Ubuntu has been installed alongside another operating system. Once all other operating systems are removed from the machine, detection of other operating systems is disabled, and to re-enable if after installing another OS, you will have to delete /boot/grub/grub.cfg and immediately run update-grub again.
>>>
>>> <unquote>
>>
>> +-----+--------+----------+------------+---------+
>> | MBR |  Swap  |  Ubuntu  |  LinuxMint |  Gentoo |
>> +-----+--------+----------+------------+---------+
>
>     Many Linux distributions ignore other installed OSes.  I used
> to use the multiple partition capability of UEFI to have many partitions
> and installed several distributions to the system and the GRUB lists
> almost always got messed up.  I switched to running them under Virtual
> Box and other such emulators could be used.
>
> bliss - brought to you by the power and ease of PCLinuxOS,
>   the Perfect Computer Linux Operating  System,
>     and a minor case of hypergraphia

I got it working again.

I used an old Boot Repair (Lubuntu-based) disc to
re-make the menu for my hard drive.

After that, I edited /etc/default/grub (Under Ubuntu)
so that I could get os-prober to run.

The os-prober is a bunch of scripts smeared around
the place, plus "grub-mounter" which is a large
executable that is part of the process. On one
occasion in the past, I only had to move one file
(/bin/os-prober) from one OS to another, to get
multi-OS detection working. It's always possible
the rest of the "script fleet" was already there,
and only os-prober was missing. But it looks complicated
enough now, you would not consider bodging all the
bits of it by hand.

In any case, once os-prober is re-enabled, the boot
order is different than it used to be, with the memtest
up too high in the menu.

[Picture]

https://i.postimg.cc/1XvCyPTy/Ubuntu-OS-Prober.gif

Ubuntu seemed to be booting slower than before, and
it was scanning for BTRFS and MDADM setups. But that was
actually the BLKID of the swap partition having been changed
by something I used, and that required editing /etc/fstab
and doing this as well.

open /etc/initramfs-tools/conf.d/resume
replace RESUME=UUID=xxx with RESUME=[the correct swap blkid!]
issue sudo update-initramfs -u
reboot your system

The boot time is back to normal on the Ubuntu partition.

Paul

On Mon, 13 Jun 2022 09:14:05 -0400, Paul wrote:

> Ubuntu seemed to be booting slower than before, and
> it was scanning for BTRFS and MDADM setups. But that was
> actually the BLKID of the swap partition having been changed
> by something I used, and that required editing /etc/fstab
> and doing this as well.
>
> open /etc/initramfs-tools/conf.d/resume
> replace RESUME=UUID=xxx with RESUME=[the correct swap blkid!]
> issue sudo update-initramfs -u
> reboot your system

Yep, anytime you use a shared swap partition across different installs
you will find that the swap UUID changes because the installer formats
the swap partition. You either reset the original swap UUID or
like me, use a partition label. Example:

$ grep swap /etc/fstab
PARTLABEL=swap swap swap defaults,nofail 0 0

Since I do not use resume I do not have to modify grub's grub.cfg