Bug#260391: Issue with grub documentation about booting a kernel only once

[Guido Trotter]

Hi!

Today I was doing some work on a new shiny remote server, and when I decided to
recompile the kernel I wanted to have a way to revert back to my the default
one, should the boot have failed...

I thus startend searching for how to do that, and I found a very confusing
situation... In particular the grub manual (in grub-doc) suggests using some
features (grub-set-default, fallback) that don't exist in the debian package,
because they have been disabled in the debian version (see:
debian/patches/revert_grub-set-default.diff in the source of the grub package)

This is reported as a normal bug against grub (#306899)
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=306899

Moreover it seems that there might be another way to achieve this, but it
doesn't seem documented in the manual itself... I was able to make this work
using the "savedefault --once --default=N" command inside grub, but I discovered
this just by looking at the BTS. There is also a grub-reboot command that does
that for you... Unfortunately this is a debian-specific feature and it's not
documented (or at least not enough... I haven't found anything about it except
in the BTS and some reference to it in the changelog).

Of course probably it's too late to revert the patch and introduce the upstream
way in sarge, but I think that the less that can be done is a huge disclaimer
about this in the README.Debian for grub and grub-doc explaining that the
feature discussed in the manual is not implemented in debian, for now, that
there is another way to achieve the result, and saying what this way is...

Since grub is now the default boot loader I think this issue might affect a lot
of people and should be fixed before the release... 

What do people think? Should we file and RC bug against grub (or grub-doc) (or
raise the severity of #260391) for "mischievous information" till a disclaimer
is added? 

Thanks,

Guido