Comment 8 for bug 1906379

Boot0000* centos HD(1,GPT,952730e9-c1fb-4ecb-9e9d-9bb55d99979f,0x800,0x100000)/File(\boot\efi\EFI\centos\shimx64.efi)

$ sudo mount /dev/disk/by-partuuid/952730e9-c1fb-4ecb-9e9d-9bb55d99979f /mnt/

$ ls /mnt/boot/efi/EFI/centos/shimx64.efi
ls: cannot access '/mnt/boot/efi/EFI/centos/shimx64.efi': No such file or directory

"\boot\efi" is the mountpoint of the ESP. But the path that needs to go into the UEFI variable should be the one relative the root of ESP. I.e. "\EFI\centos\shimx64.efi".

Plus, it is probably best to create the entry the same way that the fallback mode would create

cat /mnt/EFI/centos/BOOTX64.CSV
��shimx64.efi,CentOS Linux,,This is the boot entry for CentOS Linux

Aka, "CentOS Linux".

Whatever is creating the centos efi entry is adding a wrong prefix.