Yes, under EFI the OS can set the boot order; you can do it yourself with the "efibootmgr" command on Linux. This is used for instance by fwupd to install firmw

Yes, under EFI the OS can set the boot order; you can do it yourself with the "efibootmgr" command on Linux. This is used for instance by fwupd to install firmware updates (it temporarily changes the boot order to boot into a firmware update loader).