[conspire] upgrade and grub

[Rick Moen]

[Posting this anyway, because it's already written, just after seeing
your 'SOLVED' posting.]


Quick tip:  Putting the exact text of an error message, sometimes
prefixed by the name of your distro, sometimes finds useful things. 
In this case:

  debian The GRUB boot loader was previously installed to a disk that is no longer present

That _usually_ helps.  In this case, not a lot of the search results are
Debian-relevant.  There are a bunch that are about Ubuntu on Amazon EC2,
for example.  I see one that offers some general guidance:
https://debian-handbook.info/browse/squeeze/sect.config-bootloader.html

Among the things it mentions in passing is that recent Debian releases
have packaged both GRUB v2 _and_ the generally more popular GRUB v1 
that has lately been dubbed 'grub-legacy'.  (Confusingly, GRUB v1
releases have actual version _numbers_ in the 0.xx range.)

In Debian 8 'jessie':
https://packages.debian.org/jessie/grub-pc  (This package is GRUB2.)
https://packages.debian.org/jessie/grub-legacy

Package 'grub' is _also_ present, but merely as a virtual package that
resolves to grub-legacy.  
https://packages.debian.org/jessie/grub

I infer that unless you went rather far out of your way, what you have
installed is GRUB v1, probably GRUB v. 0.97, provided by package
'grub-legacy'.


If reading
https://debian-handbook.info/browse/squeeze/sect.config-bootloader.html,
carefully note that some sections (such as 8.8.3) are specific to GRUB2, 
and some (such as the next section, 8.8.4) are specific to GRUB v1 aka
grub-legacy.

And there's this:
http://debian.wayoflinux.com/installing/post-install/fix-common-issues/reinstall-grub

Apparently, the Official Debian installer disks now include a 'rescue
mode' option offering suboption 'Reinstall GRUB boot loader', which is
detailed on that page (in case you run into trouble).