How to get back Windows on the grub menu?

[Bo Berglund]

On Thu, 28 Oct 2021 18:23:35 +0200, Bo Berglund <bo.berglund at gmail.com> wrote:

>Is there something in here I can modify to get things working?
>
>I believe that since os-prober cannot find Windows it is no meaning to try and
>execute update-grub, right?
>Since update-grub is changing stuff I do not dare run it because I can damage my
>system further...
>
>Maybe the grub menu cannot be fixed from the Ubuntu Server 20.04.3 which was
>moved from another PC and then release-upgraded from 18.04?

NOW SOLVED!
------------
What I did was that I changed the Lenovo BIOS setting:

Startup/BootPriority changed to UEFI First from Legacy first
Then Exit/Save and the system rebooted into the menu containing Windows and
Ubuntu desktop but not my Ubuntu server.

Now I selected Ubuntu server and it loaded.

Next in a terminal I did this:
sudo os-prober
And this found both Windows and the Ubuntu server!

So next:
sudo nano /etc/default/grub

Changed the first active line:
GRUB_DEFAULT=3
(The Ubuntu server was listed on line 4, which is 3 in grub)

update-grub

And when I next rebooted the boot menu containing Ubuntu desktop, Windows, and
Ubuntu server and Ubuntu server was default, which is what I need.

So the problem was that the boot priority in Lenovo BIOS affects how the
update-grub works....


-- 
Bo Berglund
Developer in Sweden