I'm suddenly booting into BIOS/UEFI instead of to the 22.04 login screen

A few weeks back I noticed that my desktop workstation was no longer booting directly into the login screen for Ubuntu MATE 22.04, but straight to the BIOS/UEFI.

From the BIOS screen I can hit the F1 key, select the "Boot" menu and from there select which OS to boot into (but, of course, I shouldn't have to do that).

I have 22.04 on an internal nvme drive, 20.04 on a 2nd internal nvme drive, and a backup 20.04 on an internal SSD. I do not use Microsoft Windows.

I can access the GRUB menu by pressing ESC, and choose which OS to boot to from there, but I suspect some recent software update (or perhaps kernel update) caused this change.

Any tips on where I should begin to troubleshoot? And has this happened to anyone else? Thanks.

I suspect each install has its own /boot/efi partition. That's the reason you need to go to BIOS and tell it there which one to boot. Normally, there should be only one /boot/efi partition shared by all installs and grub will be able to show a menu which OS to boot.

1st nvme 22.04 ...    nvme0n1p1 /boot/efi  
                      nvme0n1p2 /

2nd nvme 20.04 ...    nvme1n1p1 /boot/efi  
                      nvme1n1p2 /

backup 20.04 ...           sda1 /boot/efi 
                           sda2 /

Check rEFInd, it can auto-detect your installed EFI boot loaders and it presents a pretty GUI menu of boot options. I have not tried it but I provide it as a reference.

There is also efibootmgr which allows you to create/modify/delete boot entries. Let's say, you decide the 1st nvme will be your boot loader for ALL installs. Using efibootmgr, you can add the 2nd nvme and the ssd. This article explains ... efibootmgr - Gentoo wiki


SOLVED. Thanks for your response. My problem was the weakening of the CMOS battery.

When I shut down, I always turn off the power supply as well as the motherboard. Yesterday I left the power supply on all night and booted today directly into the preferred OS install, instead of to the UEFI setup.

That means the battery got enough power overnight to keep all its memory intact.

Now I know that I just need to replace the battery soon.