diff --git a/merge_shim_image.sh b/merge_shim_image.sh
new file mode 100755
index 0000000000..8ba29d30fd
--- /dev/null
+++ b/merge_shim_image.sh
@@ -0,0 +1,165 @@
+#!/bin/sh
+#
+# Copyright (c) 2011 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.
+
+SCRIPT="$0"
+set -e
+
+# CGPT Header: PMBR, header, table; sec_table, sec_header
+CGPT_START_SIZE=$((1 + 1 + 32))
+CGPT_END_SIZE=$((32 + 1))
+CGPT_BS="512"
+
+STATE_PARTITION="1"
+LEGACY_PARTITIONS="8 9 10 11 12"
+RESERVED_PARTITION="9"
+
+die() {
+  echo "ERROR: $*" >&2
+  exit 1
+}
+
+# TODO(hungte) support parted if cgpt is not available
+image_get_partition_offset() {
+  cgpt show -n -i "$2" -b "$1"
+}
+
+image_get_partition_size() {
+  cgpt show -n -i "$2" -s "$1"
+}
+
+image_get_partition_type() {
+  cgpt show -n -i "$2" -t "$1"
+}
+
+image_get_partition_label() {
+  cgpt show -n -i "$2" -l "$1"
+}
+
+image_enable_kernel() {
+  cgpt add -P 1 -S 1 -i "$2" "$1"
+}
+
+image_copy_partition() {
+  local from_image="$1"
+  local from_part="$2"
+  local to_image="$3"
+  local to_part="$4"
+
+  local from_offset="$(image_get_partition_offset "$from_image" "$from_part")"
+  local from_size="$(image_get_partition_size "$from_image" "$from_part")"
+  local to_offset="$(image_get_partition_offset "$to_image" "$to_part")"
+  local to_size="$(image_get_partition_size "$to_image" "$to_part")"
+
+  if [ "$from_size" -ne "$to_size" ]; then
+    die "Failed to copy partition: $from_image#$from_part -> $to_image#$to_part"
+  fi
+
+  # TODO(hungte) Speed up by increasing bs
+  dd if="$from_image" of="$to_image" bs="$CGPT_BS" conv=notrunc \
+     count=$from_size skip="$from_offset" seek="$to_offset"
+}
+
+images_get_total_size() {
+  local image=""
+  local total="0"
+  local index
+
+  # copy most partitions from first image
+  total="$((total + CGPT_START_SIZE + CGPT_END_SIZE))"
+  for index in $STATE_PARTITION $LEGACY_PARTITIONS; do
+    total="$((total + $(image_get_partition_size "$1" $index) ))"
+  done
+
+  for image in "$1" "$2" "$3"; do
+    if [ -z "$image" ]; then
+      total="$((total + $(image_get_partition_size "$1" $RESERVED_PARTITION)))"
+      total="$((total + $(image_get_partition_size "$1" $RESERVED_PARTITION)))"
+      continue
+    fi
+    total="$((total + $(image_get_partition_size "$image" 2)))"
+    total="$((total + $(image_get_partition_size "$image" 3)))"
+  done
+  echo "$total"
+}
+
+image_append_partition() {
+  local from_image="$1"
+  local to_image="$2"
+  local from_part="$3"
+  local last_part="$(cgpt show "$to_image" | grep Label | wc -l)"
+  local to_part="$((last_part + 1))"
+  echo "image_append_partition: $from_image#$from_part -> $to_image#$to_part"
+
+  local guid="$(image_get_partition_type "$from_image" "$from_part")"
+  local size="$(image_get_partition_size "$from_image" "$from_part")"
+  local label="$(image_get_partition_label "$from_image" "$from_part")"
+  local offset="$CGPT_START_SIZE"
+
+  if [ "$last_part" -gt 0 ]; then
+    offset="$(( $(image_get_partition_offset "$to_image" "$last_part") +
+                $(image_get_partition_size "$to_image" "$last_part") ))"
+  fi
+
+  echo cgpt add "$to_image" -t "$guid" -b "$offset" -s "$size" -l "$label"
+  cgpt add "$to_image" -t "$guid" -b "$offset" -s "$size" -l "$label"
+  image_copy_partition "$from_image" "$from_part" "$to_image" "$to_part"
+}
+
+main() {
+  local force=""
+  if [ "$1" = "-f" ]; then
+    shift
+    force="True"
+  fi
+  if [ "$#" -lt 2 -o "$#" -gt 4 ]; then
+    echo "Usage: $SCRIPT [-f] output shim_image_1 [shim_2 [shim_3]]"
+    exit 1
+  fi
+
+  local image=""
+  local output="$1"
+  local main_source="$2"
+  local index=""
+  local slots="0"
+  shift
+
+  if [ -f "$output" -a -z "$force" ]; then
+    die "Output file $output already exists. To overwrite the file, add -f."
+  fi
+  for image in "$@"; do
+    if [ ! -f "$image" ]; then
+      die "Cannot find input file $image."
+    fi
+  done
+
+  # build output
+  local total_size="$(images_get_total_size "$@")"
+  # echo "Total size from [$@]: $total_size"
+  truncate "$output" -s "$((total_size * CGPT_BS))"
+  cgpt create "$output"
+  cgpt boot -p "$output"
+
+  # copy most partitions from first image
+  image_append_partition "$main_source" "$output" $STATE_PARTITION
+  local kpart=2
+  local rootfs_part=3
+  for image in "$1" "$2" "$3"; do
+    if [ -z "$image" ]; then
+      image="$1"
+      kpart="$RESERVED_PARTITION"
+      rootfs_part="$RESERVED_PARTITION"
+    fi
+    image_append_partition "$image" "$output" "$kpart"
+    image_append_partition "$image" "$output" "$rootfs_part"
+    slots="$((slots + 1))"
+    image_enable_kernel "$output" "$((slots * 2))"
+  done
+  for index in $LEGACY_PARTITIONS; do
+    image_append_partition "$main_source" "$output" "$index"
+  done
+}
+
+main "$@"