[GTALUG] Boot setup issues

[D. Joe]

On Fri, Sep 14, 2018 at 09:22:20AM -0500, o1bigtenor via talk wrote:
> Greetings
> 
> I want to have two different copies of debian on one box with the
> choice of which when I boot in.

[...]

> So I've installed both of these systems (more than once each) they
> have their own partitions for everything but boot and efi yet I'm only
> seeing one system available on grub (depending upon the last install
> as to which). 

> So I'm doing something wrong!! I tried using grub
> updating tools (# os-prober) still no joy. The web pages that I'm
> finding seem to be for an older version of grub and, as usual, I'm
> finding man pages are like reading cuneiform (which I find
> unintelligible).
> 
> This is likely something quite simple but I'm just not seeing it - - -
> please - - - some ideas/pointers?

To the best of my understanding, these tools are built with the assumption that one wants to run just the OS that invokes them.

Although the Debian wiki has some hints

https://wiki.debian.org/Grub

this seems to be more direct

https://askubuntu.com/questions/16042/how-to-get-to-the-grub-menu-at-boot-time

Are you hitting shift during boot time to get the grub menu, from which you might then be able to select amongst configured choices?

If your successful bringing up the boot-time menu, but it isn't configured to offer you the choices after holding down shift, you may have to muck around in /etc/default/grub from which update-grub et al seem to take their lead.

Take some care to dig into the boot time menu, I'm starting to see only the default (eg, the most recently installed OS) as the obvious choice at the grub top level menu during boot time, with other options buried in a submenu. (Sorry not to be more specific about how those appear--I'm favoring a quicker response over booting up a VM to see more exactly what the strings presented are).

hth,

D. Joe