Boot failure Updating Ubuntu 23.04 -23.1

My pc has 2 boot drives, Windows 11 & Ubuntu 23.04 and have been satisfied running 23.04 and
decided to update 23.04 to 23.1 via the software updater. Everything went ok until the required boot needed in order to finish the install. The reboot failed leaving a black screen displaying “grub” & “Tab” to get suggested a ton of commands, none of which made any sense to me. Long story - short, I was stuck without the ability to get to Ubuntu or boot into Windows.

During install, I selected the options to keep all current grub configurations because grub boot menu worked flawlessly for me on 23.04.

The good news is that I used a cloned drive to totally restore Ubuntu 23.04 back to the boot drive and am operational again.

I really would like to learn how to deal with this issue before the next LTS release.

Being totally ignorant about the workings of Grub, have no idea what/why this happened. I can assure you that NOBODY on this site knows LESS about grub than me so please help out this old man.

I think what may have happened is that the upgrade wrote grub to the wrong disk… ie it overwrote the windows disk

Can you boot from the windows disk now ?
That will tell you… if you cant boot windows , it wrote grub on the windows disk. Or did you restore windows too?

I think that blank screen with grub> is a grub command line prompt… it is giving you thst becsuse it cant find any grub procedure on the Ubuntu disk.
You can enter commands at that grub> prompt and make it boot from there, but it is complicated

I think the best take home message for you is… be very careful next time you install Ubuntu, at the the point where you tell the installer where to put grub… make sure it goes on the Ubuntu disk. Where it puts grub is a different thing from whether it makes a new grub configuration… you said no to that. In some distros it is possible to tell it not to write grub on any disk… I am not sure about Ubuntu.

The most important thing is… you had a backup and were able to restore it easily. Did the right thing there

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@KenS I recently updated Kubuntu and it messed with my grub menu and switched the boot order. Can you get into BIOS (F2, Escape, etc.) and see if under boot there is an “ubuntu” option? That’s what I did and selected to boot from the ubuntu drive and then my grub came up with both my Ubuntu and Linux Mint options.

Sheila Flanagan

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It will be an option to choose a disk.
Ken could probably have booted grub from the windows disk, and recovered from there.

I never got that far because the boot process was automatically initiated by the install program and hung up at the screen I described above. The only option that I had was to force a power down. The boot menu never displayed.

@nevj or a partition named Ubuntu, at least that is what shows up in my BIOS for boot order:

and when I choose Ubuntu, the grub menu shows up so I can choose between Ubuntu or LM.


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OK that is a UEFI boot… mine does not do that.

Let me add more details. The upgrade option I selected was the “Something else” option. That way I could make sure that the proper drive was selected as well as being sure the partitions & format, mount points were correct (which they were). In attempting the mandatory reboot to complete the installation, the restart initiated but stopped short of displaying the boot menu. Only the dark screen displayed as described in my initial post.

The only thing that I was able to do is press the tab key which simply rewrote the same screen with a very, very large listings of cryptic commands that were very foreign to me so my only recourse was to power down.

After the forced power down and subsequent restart, I got into the BIOS settings and I was able to access the Windows boot Manager & select Windows boot from the boot menu, and was able to boot into windows but when selecting Ubuntu, the boot failed again. At that point, I decided to reinstall Ubuntu 23.04 from a cloned drive that I made prior to my “big adventure”.

So, basically I didn’t lose anything other than a bunch of wasted time trying to upgrade to 23.1.

My feeling is that the 23.1 installation overwrote part of grub thus rendering it unusable. What confuses me is that selecting the installation options to “keep the current grub configurations” I would have circumvented all of this mess.

I have used that in Mint. It is the best choice… gives you control.

It sounds like my initial guess as to what happened was incorrect… you were able to boot windows.

There are 2 parts to grub

  • the grub program which is written in the EFI boot partition on the same disk as your Ubuntu
  • the grub configuration, which is written in the Ubuntu file system, in /boot/grub directory.

You say you told it to keep the old configuration. It may have messed that up somehow. Maybe we are not interpreting what “keep the old configuation” means correctly.
I thought it meant dont make new grub config files in Ubuntu.
Maybe it also means dont write the grub program anywhere.
In that case you would have nothing to boot with. So that option would only be used if you had another Linux in a multiboot situation, and it was looking after grub.

So , we have to find out what “keep the old configuration” in the Ubuntu installer means?
Does anyone know?

I tried upgrading this evening and this time I chose to install all of the new grub configurations (about 3 or 4) the end of the process, at the reboot stage, there was yet another selection of choosing use the current or the installer version of grub, I chose use the installer grub and everything worked.

Thanks to all who responded. Now the only issue that I have is with Grub-customizer not working. Please chime into my post concerning this issue.

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