Pack firmware into an image and do update in factory install process.

src/platform/factory_installer/factory_install.sh

Index: src/platform/factory_installer/factory_install.sh
diff --git a/src/platform/factory_installer/factory_install.sh b/src/platform/factory_installer/factory_install.sh
index 42bfea5f8d57521b4d05fb7e4b34b8766c552628..fdae9ad493243a946eddcacf0760d91ea01c6e3e 100644
--- a/src/platform/factory_installer/factory_install.sh
+++ b/src/platform/factory_installer/factory_install.sh
@@ -16,38 +16,45 @@ sleep 10
 
 # TODO(adlr): pick an install device in a matter that works on x86 and ARM.
 # This works on x86 only, afaik.
-DST=/dev/sda
+DST_DRIVE=/dev/sda
 DST_FACTORY_PART=3
 DST_RELEASE_PART=5
 DST_OEM_PART=8
 DST_EFI_PART=12
 DST_STATE_PART=1
+DST_FIRMWARE=/tmp/firmware.sh
 
 log "Factory Install: Setting partition table"
 
-/usr/sbin/chromeos-install --dst "${DST}" --skip_rootfs --run_as_root --yes \
-  2>&1 | cat >> "$MEMENTO_AU_LOG"
+/usr/sbin/chromeos-install --dst "${DST_DRIVE}" --skip_rootfs --run_as_root \
+  --yes 2>&1 | cat >> "$MEMENTO_AU_LOG"
 
 # Load the new partition table. The autoupdater has trouble with loop devices.
 sync
 echo 3 > /proc/sys/vm/drop_caches
-/sbin/sfdisk -R "$DST"
+/sbin/sfdisk -R "$DST_DRIVE"
 
 FACTORY_CHANNEL_ARG='--force_track=factory-channel'
 RELEASE_CHANNEL_ARG='--force_track=release-channel'
 OEM_CHANNEL_ARG='--force_track=oempartitionimg-channel'
 EFI_CHANNEL_ARG='--force_track=efipartitionimg-channel'
 STATE_CHANNEL_ARG='--force_track=stateimg-channel'
+FIRMWARE_CHANNEL_ARG='--force_track=firmware-channel'
 
 # Install the partitions
-for i in EFI OEM STATE RELEASE FACTORY; do
-  PART=$(eval "echo \$DST_${i}_PART")
-  CHANNEL_ARG=$(eval "echo \$${i}_CHANNEL_ARG")
-  KPART="none"
+for i in EFI OEM STATE RELEASE FACTORY FIRMWARE; do
+  if [ "$i" = "FIRMWARE" ]; then
+    DST="${DST_FIRMWARE}"
+  else
+    PART=$(eval "echo \$DST_${i}_PART")
+    DST="${DST_DRIVE}${PART}"
+  fi
 
-  log "Factory Install: Installing $i partition to $PART"
+  log "Factory Install: Installing $i image to $DST"
 
+  CHANNEL_ARG=$(eval "echo \$${i}_CHANNEL_ARG")
   SKIP_POSTINST_ARG="--skip_postinst"
+  KPART="none"
   if [ "$i" = "FACTORY" -o "$i" = "RELEASE" ]; then
     # Set up kernel partition
     SKIP_POSTINST_ARG=""
@@ -55,10 +62,11 @@ for i in EFI OEM STATE RELEASE FACTORY; do
   fi
 
   RESULT="$(/opt/google/memento_updater/memento_updater.sh --dst_partition \
-    "${DST}${PART}" --kernel_partition "${KPART}" \
+    "${DST}" --kernel_partition "${KPART}" \
     --allow_removable_boot $CHANNEL_ARG $SKIP_POSTINST_ARG)"
 
-  if [ "$RESULT" != "UPDATED" ]; then
+  # Firmware update is optional; still OK if it does not be updated.
+  if [ "$RESULT" != "UPDATED" -a "$i" != "FIRMWARE" ]; then
     log "Factory Install: AU failed"
     exit 1
   fi