I think the assumption today is that is easy to boot from some alternative media (usb/cdrom/pxe) into what used to be called a "live cd" (like Knoppix). Once th

I think the assumption today is that is easy to boot from some alternative media (usb/cdrom/pxe) into what used to be called a "live cd" (like Knoppix). Once there you can mount your existing partitions and attempt to fix any issues. The Fedora CDs have provided a "rescue" option since as long as I can remember and this attempts to find and mount your existing installation. There is also a rescue option in the grub boot list but I have never needed to use it. The Fedora docs also describe two further rescue and emergency modes available from the grub menu: https://docs.fedoraproject.org/f27/system-administrators-guide/kernel-module-driver-configuration/Working_with_the_GRUB_2_Boot_Loader.html#sec-Booting_to_Rescue_Mode https://docs.fedoraproject.org/f27/system-administrators-gui...