Grub menu shows only after shutdown but never arter reboot.

As in the subject. When I reboot the PC it boots the same OS as previously chosen. I have to do a full shutdown process to see Grub Menu and pick the other OS.

Changes in /etc/default/grub file does not make any difference.

Any idea?

I have seen it in some VM; I think it happened on EFI systems. I am not sure how to debug it though nor what happens. It could be that system goes via kexec instead of firmware reboot (at least it looks this way).

For me a reboot does not read /etc/default/grub

You are right. It doesn’t.

However, “grub2-mkconfig” does read that file when generating a new “grub.cfg”. And, during boot, “grub2” does read the resulting “grub.cfg”.

If you hibernate, it is not supposed to show a menu. Instead, it is supposed to boot into the hibernated system. I think it saves that info (what to boot to) in “/boot/grub2/grubenv”.

ok @nrickert but my problem is how to have grub menu after reboot not only after full shutdown process. Do you have any idea how to fix this?

I don’t know, because I have never experienced the same problem.

You could try removing that “grubenv” file and see whether that helps.

I resolved it by accident really.

I repeated grub recovery process and removed other drive I had in the PC. I left only the one I cloned.

After that modified /etc/default/grub again and the menu came up. Weird but worked for me.

Thanks for your help.