Updated some boxes to Fedora 30. Both using Legacy Boot and not EFI decided to reboot into a totally blank grub menu with nothing. These are boxes with traditional legacy grub and the configuration file in /boot/grub2/grub.cfg The solution was to boot a USB image and cp grub.cfg.rpmsave to grub.cfg and obviously set GRUB_ENABLE_BLSCFG=false I haven't looked into as to why blscfg doesn't work with that legacy configuration, just noticed that it happened to two different boxes. This was specially annoying on the headless box I use as a home NAS since it's usually only connected to ethernet and power so having to fix that was very annoying.
*** This bug has been marked as a duplicate of bug 1678445 ***