Trying again: I installed grub twice on two drives, how to fix it?

[Ralf Mardorf]

On Sun, 03 May 2020 09:45:38 +0000, Marco Fioretti wrote:
>Now I need to: 1)remove from grub the option to boot the HD install.
>What is the recommended way to do it, in a weird (for me now, at
>least) setup like this?  

This is not the first step. This problem might resolve itself.

>2) reconfigure/repartition the HD. Right now, what is still $HOME when
>booting the HD install is $HOME/home/marco in the SSD install, and
>this is how the HD is partitioned and mounted:  

Don't rush things. "$HOME/home/marco" is probably a typo ;).

>Device     Boot    Start       End   Sectors   Size Id Type
>/dev/sda1  *        2048    206847    204800   100M  7 HPFS/NTFS/exFAT
>/dev/sda2         206848  82238097  82031250  39,1G  7 HPFS/NTFS/exFAT
>/dev/sda3       82239488 625141759 542902272 258,9G 83 Linux  

/dev/sda3 is a root directory or just /home? IIUC it's a root directory
containing /home, but you will only keep /home, not a bootable install
on sda3, right?

Deleting the Windows NTFS partitions is no big deal. Using the freed
space by resizing sda3 after deleting sda1 and sda2 is also no problem.
Since the start address of sda3 would change, you would need to fix
grub, if you still want to boot an install on sda3. If you just want to
keep /home, then delete anything else. After deleting anything, but
/home updating the grub menu would automagically remove the old install
from the menu.

>expand (WITHOUT canceling anything it contains!!!) /dev/sda3 so it
>uses the whole HD disk, and mount it in the SSD install (which at that
>point would be the only one, of course) as /backup, or something
>similar.  

Using gparted to do the disk operations does unlike damage data, but
since some operations might not be atomic, a power outage or something
else could damage the data. I never experienced an issue, but issues
could happen, so better backup important data, before doing anything
else.

>That way, I would do all my work on the faster SSD drive, and
>use the other as storage for backups, or stuff I seldom need, being
>able to replace it any time without touching the working SSD install.  

A backup drive shouldn't be inside the computer. Remove the drive and
assemble it into an USB enclosure.