Using a master grub2 in UEFI

[Barry Jackson]

Hi,
In PC-BIOS I have always used a separate partition with it's own install 
of grub2 to boot into core.img of various grub2 based linux installations.

I am now trying to do the same with UEFI and have hit several issues.

grub2-install --grub-setup=/bin/true /dev/sda4
under PC-BIOS only installs grub2 to the grub2 directory with a copy of 
core.img in grub2/i386-pc/

Under UEFI this also makes changes in the ESP by copying 
/boot/grub2/x86_64-efi/core.efi as /boot/EFI/EFI/<vendor>/grubx64.efi 
overwriting the existing one.

How can I stop this happening?

Also, when I try to boot core.efi from another grub2 menu using 
something like:

menuentry 'Mageia-KDE sda4' {
search --no-floppy --label --set=root KDEMga4
multiboot /boot/grub2/x86_64-efi/core.efi
}

I get an error: no multiboot header found

Any help would be much appreciated.

Thanks,
Barry