installer: force updating firmware in factory install mode.

chromeos-postinst

 #!/bin/sh
 
 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script is called after an AutoUpdate or USB install. The first argument
 # is the partition where the new rootfs is installed or empty. If non-empty
 # the rootfs should be updated w/ the new bootloader config. If empty, the
 # rootfs is mounted-read only and should not be updated.
@@ skipping 86 matching lines @@
 update_firmware() {
   # See if we need to update firmware. NOTE: we must activate new firmware
   # only after new kernel is actived (installed and made bootable),
   # otherwise new firmware with all old kernels may lead to recovery screen
   # (due to new key).
   FIRMWARE_UPDATE_SCRIPT="${INSTALL_ROOT}/usr/sbin/chromeos-firmwareupdate"
   if [ ${FLAGS_update_firmware} -eq "${FLAGS_TRUE}" -a \
        -x "${FIRMWARE_UPDATE_SCRIPT}" ]; then
     FIRMWARE_UPDATE_MODE=""
     if [ -n "${IS_FACTORY_INSTALL}" ]; then
-      # factory-mode
-      FIRMWARE_UPDATE_MODE="--mode=factory_install"
+      # factory-mode (--force must be the first parameter when being invoked)
+      FIRMWARE_UPDATE_MODE="--force --mode=factory_install"
     elif [ -n "${IS_RECOVERY_INSTALL}" ]; then
       # recovery-mode
       FIRMWARE_UPDATE_MODE="--mode=recovery"
     elif [ -n "${IS_INSTALL}" ]; then
       # installation from chromeos-install
       FIRMWARE_UPDATE_MODE="--mode=recovery"
     else
       # Default: background update by Update Engine.
       # "--background-update" tells it not to perform any dangerous
       # thing that would require/cause reboot, for example re-writing
@@ skipping 287 matching lines @@
     echo "marking part $LEGACY_PART_NUM bootable (new)"
     "${INSTALL_ROOT}"/usr/bin/cgpt boot -i $LEGACY_PART_NUM ${ROOT_DEV} 2>&1
   else
     # The old gpt tool requires a -b arg to specify the PMBR bootcode. We don't
     # want to change the code, so we have to extract it, then put it back.
     dd if=${ROOT_DEV} bs=512 count=1 of=/tmp/oldpmbr.bin
     echo "marking part $LEGACY_PART_NUM bootable (old)"
     gpt -S boot -i $LEGACY_PART_NUM -b /tmp/oldpmbr.bin ${ROOT_DEV} 2>&1
   fi
 fi