@cblackman welcome to ask.fedora
I googled the message (ERROR: Invalid Arch Independent ELF Magic) and saw that it is not a specific fedora problem … it seams that a file from grub got corrupted and is not writable anymore. So a
of grub should replace the corrupt file and fix the boot problem.
I took a link who is 7 years old and not from the fedora community:
(Debian GRUB rescue - "invalid arch independent ELF magic" - Stack Overflow)