grub: cutmem
16.3.20 cutmem
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-- Command: cutmem from[K|M|G] to[K|M|G]
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 'badram' command.
Note: The command is not allowed when lockdown is enforced (⇒
Lockdown). This prevents removing EFI memory regions to
potentially subvert the security mechanisms provided by the UEFI
secure boot.