Based on this answer for detecting the boot loader I ran sudo dd if=/dev/sda bs=512 count=1 2>&1 | grep GRUB
and it matched. However, I'm pretty sure I'm running Gummiboot since modifying /boot/loader/entries/arch.conf
affected my boot. Does an EFI boot loader like Gummiboot not modify the MBR, or am I misunderstanding something? Is it a problem if I have "enabled" both?
Related to enabling Intel microcode updates.