How to restore the MBR after do-release-upgrade?

blind Pete 0123peter at gmail.com
Sun Jul 10 13:50:13 UTC 2016


Tom H wrote:

> On Fri, Jul 8, 2016 at 3:18 PM, Ralf Mardorf <silver.bullet at zoho.com>
> wrote:
>> On Fri, 8 Jul 2016 14:59:40 +0200, Liam Proven wrote:
> 
> 
>>>> What ever bootloader I use, how can I prevent the Ubuntu install from
>>>> overwriting an existing bootloader next time I run
>>>> do-release-upgrade?
>>>
>>> If it's in *that installation's own root filesystem* then that is
>>> where it should stay.
>>
>> Thank you for the pointer.
>>
>> The do-release-upgrade only offers /dev/sda and /dev/sdb. Assumed it's
>> installed to the root fs (?partition of the root fs?), then a
>> do-release-upgrade recognises this?
> 
> grub upstream discourages the installation of grub to a partition so
> you have to use "--force" in order to do so.
> 
> I haven't used either Ubuntu installers for a while but I doubt that
> Ubiquity allows the above and d-i allows you to enter a partition
> after choosing "other" when prompted to install grub.
> 
> do-release-upgrade probably respects debconf so if you run
> "dpkg-reconfigure -p low grub-pc" (on bios firmware), you'll be able
> to set a partition as the grub-install destination.
> 
> 
>> That at least would be a good workaround, IMO still the better solution
>> would be, if Ubuntu would stop enforcing installing a bootloader.
> 
> It's the kernel that depends on grub. It makes sense for Ubuntu to do
> so because, if a user's not installing in a container (and therefore
> not in need of a kernel), he doesn't need a bootloader.

I don't think that the kernel does depend on grub.  Try rEFInd on UEFI 
machines and LiLo on BIOS machines.  

One of my machines has LiLo on the mbr of two of its hard drives (and a 
floppy) as well as the root partitions of each of the installations, about
eight all up.  On power up it goes to /dev/sda to /dev/sda6 to Ubuntu - 
unless I intervene.  

-- 
blind Pete
Sig goes here...  




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