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

[Ralf Mardorf]

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?

That at least would be a good workaround, IMO still the better solution
would be, if Ubuntu would stop enforcing installing a bootloader.

Regards,
Ralf