Add script to in-place modify a recovery image to ssd

scripts/image_signing/sign_official_build.sh

 #!/bin/bash
 
 # Copyright (c) 2010 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.
 
 # Sign the final build image using the "official" keys.
 #
 # Prerequisite tools needed in the system path:
 #
@@ skipping 394 matching lines @@
   extract_image_partition ${OUTPUT_IMAGE} 4 ${temp_kimageb}
   ${SCRIPT_DIR}/resign_kernel_partition.sh ${temp_kimageb} ${temp_out_vb} \
     ${KEY_DIR}/kernel_data_key.vbprivk \
     ${KEY_DIR}/kernel.keyblock \
     "${KERNEL_VERSION}"
 
   # Copy the installer vblock to the stateful partition.
   # TODO(gauravsh): Remove this if we get rid of the need to overwrite
   # the vblock during installs. Kern B could directly be signed by the
   # SSD keys.
+  # Note: This vblock is also needed for the ability to convert a recovery
+  # image into the equivalent SSD image (convert_recovery_to_ssd.sh)
   local stateful_dir=$(make_temp_dir)
   mount_image_partition ${OUTPUT_IMAGE} 1 ${stateful_dir}
   sudo cp ${temp_out_vb} ${stateful_dir}/vmlinuz_hd.vblock
 
   echo "Signed recovery image output to ${OUTPUT_IMAGE}"
 }
 
 # Generate the factory install image.
 sign_for_factory_install() {
   ${SCRIPT_DIR}/resign_image.sh ${INPUT_IMAGE} ${OUTPUT_IMAGE} \
@@ skipping 54 matching lines @@
   resign_firmware_payload ${INPUT_IMAGE}
   update_rootfs_hash ${INPUT_IMAGE} \
     ${KEY_DIR}/installer_kernel.keyblock \
     ${KEY_DIR}/installer_kernel_data_key.vbprivk \
     2
   sign_for_factory_install
 else
   echo "Invalid type ${TYPE}"
   exit 1
 fi