Grub2 and multiple boot different ubuntu versions

[Tom H]

>> I don't really understand this "own partition" option. Won't there
>> still be one of the OSs whose update-grub will update grub.cfg?

> I had written in separate thread on subject, The OS's grub will continue
> be updated with each kernel change or update-grub, but the 'first grub'
> will remain and will boot to the latest kernel of any OS.

Thanks. I have now seen your two instruction emails and will read them
carefully as soon as a I have a chance. I know the principle; I am
just curious about the update-grub mechanics.