kovacsakosIt is safe to directly edit /boot/grub2/grub.cfg in Fedora. Grubby in Fedora modifies the configuration when a kernel update is performed but does so in a safe manner. Other distributions, in particular Debian and Debian derives distributions have a distribution specific patch that adds a update-grub command. This is not included in Fedora and not required either.
http://fedoraproject.org/wiki/Grub2#Updating_Grub_configuration