I have 2 Hard drives, I have Ubuntu 19.10 on my big one, and just installed Endeavour on the smaller one. I’ve always found it just easier to unplug the drive, I’m not installing the OS on.
Both work great, but I have to go through the Bios to use Ubuntu.
Endeavour says Grub is loading, but its very quick, and goes right to an Endeavour only listing.
I don’t care which drive it gets installed upon, as long I can select the OS.
If you want EndeavourOS to boot to grub and have Ubuntu in the grub menu just run this in the terminal.
sudo grub-mkconfig -o /boot/grub/grub.cfg
Edit: After you may have to set the boot drive to be the one EndeavourOS is installed on.
When you do the Grub config command, BOTH drives have to be active - there is an app called os-prober that Grub will run to see what else is on there, and create the extra entries for you. If you are getting grub now, it will probably continue to be the ‘controlling’ boot manager, so that should be all that is required. Ubuntu is easily found and sets up without difficulty for EndeavourOS, but the reverse is not so (I can explain if you want) so things work out much better with EndeavourOS in charge
Ya sorry i forgot to add that if he has the drive disconnected it wouldn’t work too well.
I think that advice is only remembered by those who forgot it once!
Some great information on grub here (I’ve bookmarked it and referred to it several times):
Do you actually type that whole thing out? AUR update-grub. I can’t ever remember all of that mkconfig stuff.
I don’t know what @ricklinux does, but I have a directory “Useful”, which has any number of handy things sitting there, ready to be copy/pasted - things like the above, and a dd command ready to write a USB stick with an ISO - even an updated sudo blkid output, 'cos it comes up so often
There is almost no way I could remember very many of these things in sufficient detail otherwise - getting ancient now…
I’m ok with a cheat sheet. I’m way too lazy to type all of that out everytime though. That’s crazy.
CRTL-SHIFT-V is your friend… I doubt I could ever have survived Linux since Ubuntu 6.06 without it!
I keep a cheat sheet for lots of commands that I can’t remember. For example, to remove orphan packages: pacman -Rns $(pacman -Qtdq).
The 2nd hard drive was plugged in, and that simple worked perfectly.
Thank you very much for all your help.