Create a fourth partition to put the raw kernel image in.

src/scripts/image_to_usb.sh

 #!/bin/bash
 
 # 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.
 
 # Script to convert the output of build_image.sh to a usb image.
 
 # Load common constants.  This should be the first executable line.
 # The path to common.sh should be relative to your script's location.
 . "$(dirname "$0")/common.sh"
 
 
 # Flags
 DEFINE_string board "" "Board for which the image was built"
 DEFINE_string from "" \
   "Directory containing rootfs.image and mbr.image"
 DEFINE_string to "" "$DEFAULT_TO_HELP"
 DEFINE_boolean yes $FLAGS_FALSE "Answer yes to all prompts" "y"
 DEFINE_boolean install_autotest $FLAGS_FALSE \
   "Whether to install autotest to the stateful partition."
+DEFINE_boolean copy_kernel $FLAGS_FALSE \
+  "Copy the kernel to the fourth partition."
 
 # Parse command line
 FLAGS "$@" || exit 1
 eval set -- "${FLAGS_ARGV}"
 
 # Inside the chroot, so output to usb.img in the same dir as the other
 # Script can be run either inside or outside the chroot.
 if [ $INSIDE_CHROOT -eq 1 ]
 then
   AUTOTEST_SRC="/usr/local/autotest/${FLAGS_board}"
@@ skipping 120 matching lines @@
   then
     sudo mount "${LOOP_DEV}" "${STATEFUL_DIR}"
     install_autotest
   fi
   sync
   sudo losetup -d "$LOOP_DEV"
   sync
 
   trap - EXIT
 
+  if [ $FLAGS_copy_kernel -eq $FLAGS_TRUE ]
+  then
+    echo "Copying Kernel..."
+    "${SCRIPTS_DIR}"/kernel_fetcher.sh \
+      --from "${FLAGS_from}" \
+      --to "${FLAGS_to}" \
+      --offset "$(( ($PART_SIZE * 3) + 512 ))"
+  fi
+
   echo "Copying MBR..."
   sudo "${SCRIPTS_DIR}"/file_copy.py \
     if="${FLAGS_from}/mbr.image" of="$FLAGS_to"
   sync
   echo "Done."
 else
   # Output to a file, so just cat the source images together
 
   PART_SIZE=$(stat -c%s "${FLAGS_from}/rootfs.image")
 
@@ skipping 23 matching lines @@
   echo "Done.  To copy to USB keyfob, outside the chroot, do something like:"
   echo "   sudo dd if=${FLAGS_to} of=/dev/sdb bs=4M"
   echo "where /dev/sdb is the entire keyfob."
   if [ $INSIDE_CHROOT -eq 1 ]
   then
     echo "NOTE: Since you are currently inside the chroot, and you'll need to"
     echo "run dd outside the chroot, the path to the USB image will be"
     echo "different (ex: ~/chromeos/trunk/src/build/images/SOME_DIR/usb.img)."
   fi
 fi