Grub Customizer Messed Up Grub - How Reinstall Grub Properly?

Question

Grub Customizer messed up my Grub. I regret ever installing it. I purged Grub Customizer, but how do I reinstall Grub? Here is my story:

---

I had a dual-boot system, combining Windows 11 and Ubuntu 22.04 with Grub. At startup, Grub would show several entries, which I found a bit annoying. I just wanted two simple entries:

• Ubuntu
• Windows

So I installed Grub Customizer on Ubuntu and customized my boot window. Simply stated - I removed all the entries that puzzled me, just keeping one entry for Ubuntu and one for Windows.

I looked at it and was happy. Until now. Today, Ubuntu 22.04 offered me an upgrade to Ubuntu 23.10. I accepted.

Now, my Grub boot window looks like this (without the numbers on the left):

1  Ubuntu
2  Advanced options for Ubuntu
3  Memory test (memtest86+x64.efi)
4  Memory test (memtest86+x64.efi, serial console)
5  Windows Boot Manager (on /dev/nvme0n1p1)
6  Windows Boot Manager (on /dev/nvme0n1p1)
7  UEFI Firmware Settings

I have two questions:

QUESTION 1:
There are now two entries to start Windows 11: line 5 and line 6. They are identical. Why is that entry duplicated? How can I get rid of this duplication?

QUESTION 2:
Can I change the order of the entries, without resorting to Grub Customizer? I also don't want to edit files that are not supposed to be edited (which could give problems when running another grub update in the future).

I already tried to re-install Grub, from within my Ubuntu. This is what happened:

```sh
$ sudo grub-install /dev/sdX
Installing for x86_64-efi platform
Installation finished. No error reported.
$ sudo update-grub
Sourcing file `/etc/default/grub'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-6.5.0-14-generic
Found initrd image: /boot/initrd.img-6.5.0-14-generic
Found linux image: /boot/vmlinuz-6.2.0-39-generic
Found initrd image: /boot/initrd.img-6.2.0-39-generic
Found memtest86+ 64bit EFI iimage: /boot/memtest86+x64.efi
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Windows Boot Manager on /dev/nvme0n1p1@/EFI/Microsoft/Boot/bootmgfw.efi
Adding boot menu entry for UEFI Firmware Settings ...
/etc/grub.d/proxifiedScripts/linux: 1: version_find_latest: not found
I'm not sure if this re-installation of Grub succeeded or failed. It outputs `/etc/grub.d/proxifiedScripts/linux: 1: version_find_latest: not found` in the end, so I'm confused.
</code></pre>
<p>By the way, this is my grub version:</p>
<pre class="lang-sh prettyprint-override"><code>$ grub-install --version
grub-install (GRUB) 2.12~rc1-10ubuntu4
</code></pre>
<p><strong>EDIT 1</strong><br>
I found some tutorials about how to re-install Grub from a live Linux USB-drive. However, the steps given are too complex (not detailed enough). They require a level of Linux knowledge I simply don't have at the moment.</p>
<p><strong>EDIT 2</strong><br>
From the comments:</p>
<blockquote>
<p>[@guiverc] I'd check you've not done something risky to your system if the details in your question are correct; <code>Ubuntu 22.04 LTS</code> does not currently offer an upgrade to <code>23.10</code>, only to <code>23.04</code> as per <code>changelogs.ubuntu.com/meta-release</code> (ie. lunar is the next release that is supported, thus where upgrade will currently go). Your details as outlined in the question highlight a potential problem in your system that I'd suggest exploring (or your question itself is missing facts)</p>
</blockquote>
<p>I have no idea. All I know is that Ubuntu offered me this upgrade, and I went for it. Now I have this version running:</p>
<pre class="lang-sh prettyprint-override"><code>$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 23.10
Release:    23.10
Codename:   mantic
</code></pre>