Grub bootloader gone after upgrade from 22.04 LTS to 24.04 LTS

Ubuntu Version:
22.04 LTS → 24.04 LTS

Desktop Environment (if applicable):
Gnome

Problem Description:
I use a Windows 10 / Ubuntu dual-boot set-up on my personal workstation. Yesterday, I upgraded Ubuntu from 22.04 LTS to 24.04 LTS. The upgrade went well, but after reboot, I no longer have access to the Grub multi-boot menu.

Relevant System Information:
Dual-boot setup with Ubuntu 22.04 and Windows 10

Screenshots or Error Messages:
Bootinfo report generated by boot repair: Ubuntu Pastebin

What I’ve Tried:
From the BIOS boot menu, I tried manually booting into Windows and Ubuntu. Windows works perfectily but I cannot boot into Ubuntu. From Windows, I flashed a Ubuntu Live image in a USB stick and booted into it. I have checked all my partitions are still there with no apparent data loss. So, I installed boot-repair and generated a boot-info report (see above). It has suggested some “recommended” fixes but I read I should get advice before applying them. So here I am.
Can someone help me?

Look at line 304 of boot repair. You may need to reinstall grub as suggested by boot repair as you have updated to a new OS. Do you have Secure Boot on? If so, disable it and try booting the Ubuntu entry from the BIOS. If that boots then you should likely reinstall grub to purge the old entry and reinstall grub. You said you cannot boot Ubuntu but neglected to indicate what happens which would be useful information to get help. Do you see a blank screen, a blkinking cursor, a grub prompt (grub>) or something else.

Are you sure the upgrade to 24.04 went OK?

Line 86: OS#1 (linux): Ubuntu 22.04.5 LTS on sda5
Line280: boot/vmlinuz-5.15.0-130-generic
Kernel 5.15.0 is from Ubuntu 22.04

Thanks for your answer.

When I try to boot Ubuntu, I get a black screen and then the PC just reboots again, with no message I can see on the screen. When I check in Windows, secure boot seems disabled.

Do you have good backups. Fallback if upgrade does not work is new install.

nVidia often makes it a bit more difficult. Typically you have to have system fully updated and uninstall all proprietary drivers before upgrade. Then after upgrade reinstall proprietary drivers. Best version of nVidia driver may be different and you always purge before new install of nvidia driver.

Can you boot to recovery mode from grub menu? If you press escape just after UEFI/BIOS screen but before grub menu normally appears, do you then get menu. And then boot recovery mode to a terminal to purge nVidia & update to 24.04.

I used to upgrade, but since drives became larger, now have (at least) two / (root) partitions. And then do a new clean install, alternating LTS versions as main working install. I keep /home inside / to avoid conflicts, but have large data partition for all my data, the folders normally in /home & link data back into /home. And back up /home, data, & list of installed apps to make it easy to restore.

I do not have access to grub this is one of my issues: grub seems… gone.

My /home partition is separate from / so, I can re-install from scratch without losing much data. I will have to reinstall everything else though.

So what do I try?

  • Apply boot-repair recommendations? (re install grub)
  • New install of Ubuntu from scratch?

My priorities are to keep my dual-boot and leave Windows and /home partitions untouched.

It certainly seems that the upgrade failed, therefore a new install of Ubuntu 24.04 would be sensible.
Even if your /home is separate, you must still have solid backups of both your Windows and Ubuntu personal files.

I’d try reinstalling grub from boot repair since you have backups and a separate /home partition. If you decide to install 24.04 instead of doing another update/upgrade, during the install do NOT format the / or /home partitions during the install.

So, what I did is reinstall a vanilla Ubuntu 24.04 from the live USB image. On the next boot, I reached grub shell. I booted into the Ubuntu manually from there and ran boot-repair.
Now everything is working.

I did format / as I wanted to start from a clean slate. Why do you think it is a bad idea (home data in another partition) ?

Using a separate partition for /home or a separate /data partition is very common and simplifies things. If you are reinstalling you need to make sure the /home partition is not selected to format if you see that option. I’ve reinstalled another Linux OS a number of times without formatting the / partition and it has always been successful and personal data on the partition was always retained.

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