On Apr 7, 2020, at 04:14, Alessandro Baggi <alessandro.baggi at gmail.com> wrote: > thank you for your explanation. So in el8 grubby should be used to update kernel opts and grub2-mkconfig is used to generate an initial config. > > If I'm not wrong, grubby updates every single (sperated) entries on /boot/loader/entries and then generate the /boot/efi/EFI/centos/grub.cfg? > > Suppose that I want use only grub2-mkconfig to generate the grub.cfg what other operation are needed to make it working? grubby only alters the existing configuration. It never regenerates the grub.cfg in EFI. You can’t use “grub2-mkconfig” to create individual boot spec entries. -- Jonathan Billings <billings at negate.org>