If your computer is booting with a UEFI BIOS you may notice that changes you make to /etc/default/grub are not taking effect. This may be because you are generating grub.cfg in the wrong location.

Make your changes to /etc/default/grub (kernel options are set on the GRUB_CMDLINE_LINUX= line). Now regenerate your grub.cfg in the standard non-EFI location:

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

And/or in the EFI location:

sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg

Alternatively, you can reference your grub config via the symbolic link in /etc. On UEFI:

sudo grub2-mkconfig -o /etc/grub2-efi.cfg

On non-UEFI BIOS:

sudo grub2-mkconfig -o /etc/grub2.cfg