A friend has a PC, ASUS Z97M-PLUS, happily running CentOS 8.x. It was originally installed in UEFI mode (with secure boot) using media ‘CentOS-8-x86_64-1905-dvd1.iso’.
I want to install Rocky (8 or 9), but it fails straight away with the error:
Failed to read header: Unsupported
Failed to load image: Unsupported
start_image() returned Unsupported
I know this is partly to do with the EFI firmware being old, but I think it’s also to do with the “shim”, BOOTX64.EFI.
The Fedora people have a very clear explanation of the issue and a work-around at this link:
They are saying to use an older “shim”, but should I really be trying to bury a Fedora file inside Rocky, and even if I was able to boot, would it just break at the next DNF upgrade?