Re: Dual boot. Ubuntu update removes Debian GRUB.

From	Felix Miata <mrmazda@earthlink.net>
Newsgroups	linux.debian.user
Subject	Re: Dual boot. Ubuntu update removes Debian GRUB.
Date	2016-09-01 21:50 +0200
Message-ID	<scG9Q-65j-11@gated-at.bofh.it> (permalink)
References	<scFnr-5wI-9@gated-at.bofh.it>
Organization	less than infinite

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Stefan.schultz19.5.1991 composed on 2016-09-01 14:30 (UTC-0400):

> Dual boot. Ubuntu update removes Debian GRUB.

> Last week I installed a few updates to Ubuntu 14.04. It installed the updates and then froze whilst installing Ununtu's grub. After the re-boot, Ubuntu was the only choice of O/S. No sign of Debian.

> After a few hours I finally got Debian recovery to reinstall the Grub on the MBR of the SSD.

> Some notes.

> 128GB SSD /dev/sda (GRUB finally reinstalled here)

> Partions

> 60GB Ubuntu /dev/sda1
> 4GB Ubuntu swap /dev/sda8
> 54GB Debian 'Jessie' /dev/sda7 (unlocked)
> 6GB Debian swap /dev/sda6 (unlocked)

> GRUB

> 4GB Debian GRUB /dev/sda5 (will not boot from this)
> Ubuntu boot loader is installed here too.

> Encrypted partitions

> 54GB Debian 'Jessie' /dev/mapper/sda7_crypt
> 6GB Debian swap /dev/mapper/sda6_crypt

> TWO QUESTIONS.

> 1/ Can anybody explain why the Ubuntu update deleted/removed the Debian GRUB?

Last installed wins always. This gets repeated at update time of a previous 
installation, which is what just happened to you.

This has been explained countless times countless places. Whenever any 
subsequent installation is performed, Windows or Linux, the subsequent 
installer will overwrite the MBR with native code - *unless* you take 
affirmative steps to prevent it from doing so. The how and why is somewhat 
complicated, so in simplest terms, the best thing to do is disallow 
installing anything to the MBR. In practical terms you can't do this with 
Windows, so if Windows will be subsequent, then all you can to is take steps 
in advance to minimize the disruption and ease recovery, something easily 
done in about a minute if familiar with the process and planned for.

> 2/ Is there a Debian approved GRUB boot customizer? I can't find one
> mentioned anywhere.

Booted to Ubuntu, running os-prober ought to find Debian and put it in its 
Grub2 menu. If you want Debian to be the default, first either reconfigure 
the default selection in Ubuntu, or boot Debian to have it reinstall the 
bootloader. On very next boot to Ubuntu, reconfigure Ubuntu to boot from its 
/ partition.

> Is it possible to resolve this? This would be a pain in the butt, if I had
> to do this at every Ubuntu update!

At least one of the of the two installations needs to have its bootloader 
reconfigured to its / partition instead of MBR.
-- 
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/

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Thread

Dual boot. Ubuntu update removes Debian GRUB. "Stefan.schultz19.5.1991" <stefan.schultz19.5.1991@protonmail.com> - 2016-09-01 21:00 +0200
  Re: Dual boot. Ubuntu update removes Debian GRUB. Brian <ad44@cityscape.co.uk> - 2016-09-01 21:50 +0200
  Re: Dual boot. Ubuntu update removes Debian GRUB. Felix Miata <mrmazda@earthlink.net> - 2016-09-01 21:50 +0200

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