Red Hat and CentOS systems aren’t booting due to BootHole patches 6 years ago
As usual, there are prophetic warnings from Linus:
https://yarchive.net/comp/linux/efi.html
BIOS should be simple, because it is buggy anyway. Handing over to a bootloader in the MBR is all that a BIOS should do. Now one is at the mercy of NVRAM, grub2 and loads of gratuitous complexity.