core/system/boot/grub2/files/30_uefi-firmware-new

#! /bin/sh
set -e

# grub-mkconfig helper script.
# Copyright (C) 2012  Free Software Foundation, Inc.
#
# GRUB is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GRUB is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

prefix="/usr"
exec_prefix="/usr"
datarootdir="/usr/share"

export TEXTDOMAIN=grub
export TEXTDOMAINDIR="${datarootdir}/locale"

. "${datarootdir}/grub/grub-mkconfig_lib"

efi_vars_dir=/sys/firmware/efi/efivars
EFI_GLOBAL_VARIABLE=8be4df61-93ca-11d2-aa0d-00e098032b8c
OsIndications="$efi_vars_dir/OsIndicationsSupported-$EFI_GLOBAL_VARIABLE"

if [ -e "$OsIndications" ] && \
   [ "$(( $(printf 0x%x \'"$(cat $OsIndications | cut -b1)") & 1 ))" = 1 ]; then
  LABEL="System setup"

  gettext_printf "Adding boot menu entry for EFI firmware configuration\n" >&2

  onstr="$(gettext_printf "(on %s)" "${DEVICE}")"

  cat << EOF
if [ "\$grub_platform" = "efi" ]; then
	fwsetup --is-supported
	if [ "\$?" = 0 ]; then
		menuentry '$LABEL' \$menuentry_id_option 'uefi-firmware' {
			fwsetup
		}
	fi
fi
EOF
fi

#See for EFI present
if [ -d /sys/firmware/efi ]; then

. "/usr/share/grub/grub-mkconfig_lib"

#See for Windows EFI string in EFI BIOS
WINDOWS_EFI=$(/usr/sbin/efibootmgr -v | grep -E -m 1 '(WINDOWS|Windows Boot Manager)' | sed 's/.*\(HD([^()]*)File([^()]*)\).*/\1/i')
if [ -z "$WINDOWS_EFI" ]; then
        exit 0
fi
WIN_EFI_PATH_LINUX=/EFI/Microsoft/Boot/bootmgfw.efi

#Determine EFI UUID
WIN_EFI_UUID=$(grub2-probe --target=fs_uuid /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi)

ESP_SEARCH_HINTS=$(grub2-probe --target=hints_string /boot/efi/EFI/Microsoft/Boot/bootmgfw.efi)

cat << EOF
menuentry "Windows Boot Manager" {
EOF
save_default_entry | sed -e "s/^/  /"
cat << EOF
  insmod part_gpt
  insmod fat
  insmod search_fs_uuid
  insmod chain
  search --fs-uuid --set=root ${ESP_SEARCH_HINTS} ${WIN_EFI_UUID}
  chainloader $WIN_EFI_PATH_LINUX
}
EOF

fi