Grub not picking the latest kernel automatically on boot

Ask Fedora
1

Hello there, when rebooting my machine, the latest installed kernel is picked during the boot process, all good, but in case I shutdown and start it again (cold reboot), the grub menu shows no countdown and I have to select manually a kernel. I am on Fedora 43 xfce.

I decided to install fedora 43 xfce on a virtual machine (since I thought the grub config would differ from mine since it remained untouched the last 2+ years), edited the grub menu there (also run sudo grub2-mkconfig -o /etc/grub2.cfg ) and I saw that it does pick a kernel automatically (i.e. in a virtual environment works, in bare metal does not)

This is now my /etc/default/grub (same as the one working from a fresh install in a virtual machine)

GRUB_TIMEOUT=3
GRUB_DISTRIBUTOR=“$(sed ‘s, release .*$,g’ /etc/system-release)”
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT=“console”
GRUB_CMDLINE_LINUX=“rd.luks.uuid=luks-14f068cc-3b2b-4227-a4e2-5375316de012 rhgb quiet”
GRUB_DISABLE_RECOVERY=“true”
GRUB_ENABLE_BLSCFG=true

any idea on what could be the reason of the latest selected kernel not being picked automatically after a cold reboot? Thank you for reading these lines

2

Try this and check if the issue persists:

sudo grub2-editenv - list
sudo grub2-editenv - create
3

It is often cause by a value in the grubenv file. To list

sudo grub2-editenv - list

If you have the variable “saved_entry” in the listing, run this to clear it

sudo grub2 -editenv - unset saved_entry
4

In addition to what the others already said, one possible reason for this is that /boot is on BTRFS file system (which is not the default, but it can be set up this way, AFAIK). This prevents grub from writing to the grubenv file.

5

Hi Lars,

$lsblk -f

outputs ext4 as the /boot’s filesystem, the issue seems to be something else. Thank you for your answer

6

Hello Vladislav, that did not solve the issue.

after

$sudo grub2-editenv - create

now

$ sudo grub2-editenv - li

outputs

boot_success=0

but now the grub menu shows the countdown for about ~0.1 seconds and then the countdown is gone and no kernel is automatically picked. Thank you for your reply

7

That is fixed in Fedora 44.

That is the purpos of the line env_block=512+1 line in the grubenv file.