Hello,
I noticed that efibootmgr is not usable with standard fog kernel (EFI variables are not supported on this system).
I used the documentation https://wiki.fogproject.org/wiki/index.php?title=Build_TomElliott_Kernel#Build_TomElliott_Kernel_for_FOG_0.33b_and_newer to compile the kernel and changed only this option:
EFI (Extensible Firmware Interface) Support
<*> EFI Variable Support via sysfs
and now efibootmgr is working. Can you activate this option by default in the fog kernel ?