I need to rescue an unbootable UEFI Fedora 26 system.
I have booted from the DVD, and used the rescue choot environment. I have a GPT disk with a small FAT32 ESP partition of type EF00.
dnf reinstall grub2-efi grub2-efi-modules shim grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
as described here: https://fedoraproject.org/wiki/GRUB_2
The grub.cfg file looks plausible. The system boot menu shows a "Fedora" entry, but it is not actually bootable.
What else do I need to do?