efibootmgr: option requires an argument -- 'd' efibootmgr version 15 grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.

This sometimes happens when trying to install the EFI version of grub to a device when you are booted into Legacy/MBR mode. It doesn't seem to occur on all machines, but some and seems somewhat BIOS dependent.

grub-install --target=x86_64-efi /dev/sda Installing for x86_64-efi platform. grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. EFI variables are not supported on this system. efibootmgr: option requires an argument -- 'd' efibootmgr version 15 usage: efibootmgr [options] -a | --active sets bootnum active -A | --inactive sets bootnum inactive -b | --bootnum XXXX modify BootXXXX (hex) -B | --delete-bootnum delete bootnum -c | --create create new variable bootnum and add to bootorder -C | --create-only create new variable bootnum and do not add to bootorder -D | --remove-dups remove duplicate values from BootOrder -d | --disk disk (defaults to /dev/sda) containing loader -r | --driver Operate on Driver variables, not Boot Variables. -e | --edd [1|3|-1] force EDD 1.0 or 3.0 creation variables, or guess -E | --device num EDD 1.0 device number (defaults to 0x80) -g | --gpt force disk with invalid PMBR to be treated as GPT -i | --iface name create a netboot entry for the named interface -l | --loader name (defaults to "\EFI\ubuntu\grub.efi") -L | --label label Boot manager display label (defaults to "Linux") -m | --mirror-below-4G t|f mirror memory below 4GB -M | --mirror-above-4G X percentage memory to mirror above 4GB -n | --bootnext XXXX set BootNext to XXXX (hex) -N | --delete-bootnext delete BootNext -o | --bootorder XXXX,YYYY,ZZZZ,... explicitly set BootOrder (hex) -O | --delete-bootorder delete BootOrder -p | --part part (defaults to 1) containing loader -q | --quiet be quiet -t | --timeout seconds set boot manager timeout waiting for user input. -T | --delete-timeout delete Timeout. -u | --unicode | --UCS-2 handle extra args as UCS-2 (default is ASCII) -v | --verbose print additional information -V | --version return version and exit -w | --write-signature write unique sig to MBR if needed -y | --sysprep Operate on SysPrep variables, not Boot Variables. -@ | --append-binary-args file append extra args from file (use "-" for stdin) -h | --help show help/usage grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.