Remove any memory regions in specified range.
This command notifies the memory manager that specified regions of RAM ought to be filtered out. This remains in effect after a payload kernel has been loaded by GRUB, as long as the loaded kernel obtains its memory map from GRUB. Kernels that support this include Linux, GNU Mach, the kernel of FreeBSD and Multiboot kernels in general.
The command is similar to
Note: The command is not allowed when lockdown is enforced (see Lockdown). This prevents removing EFI memory regions to potentially subvert the security mechanisms provided by the UEFI secure boot.