diff --git a/build_gpt.sh b/build_gpt.sh
index f9179b2b8d..d9346202f0 100755
--- a/build_gpt.sh
+++ b/build_gpt.sh
@@ -130,6 +130,7 @@ if [[ "$ARCH" = "arm" ]]; then
     hexdump -v -C "$MBR_IMG"
   else
     echo "Error: u-boot mkimage not found or not executable."
+    exit 1
   fi
   PMBRCODE=${MBR_IMG}
 else
@@ -140,6 +141,9 @@ fi
 # describing the partition table entries (see the comments in the source).
 install_gpt $OUTDEV $ROOTFS_IMG $KERNEL_IMG $STATEFUL_IMG $PMBRCODE
 
+# Emit helpful scripts for testers, etc.
+${SCRIPTS_DIR}/emit_gpt_scripts.sh "${OUTDEV}" "${IMAGEDIR}"
+
 # Now populate the partitions.
 echo "Copying stateful partition..."
 dd if=${STATEFUL_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_STATEFUL}
@@ -150,3 +154,7 @@ dd if=${KERNEL_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_KERN_A}
 echo "Copying rootfs..."
 dd if=${ROOTFS_IMG} of=${OUTDEV} conv=notrunc bs=512 seek=${START_ROOTFS_A}
 
+# Clean up temporary files.
+if [[ -n "${MBR_IMG:-}" ]]; then
+  rm "${MBR_IMG}"
+fi
diff --git a/build_image b/build_image
index dbe62a74be..b6b665a6b5 100755
--- a/build_image
+++ b/build_image
@@ -69,7 +69,6 @@ IMAGE_SUBDIR="${CHROMEOS_VERSION_STRING}-a${FLAGS_build_attempt}"
 OUTPUT_DIR="${FLAGS_output_root}/${FLAGS_board}/${IMAGE_SUBDIR}"
 ROOT_FS_DIR="${OUTPUT_DIR}/rootfs"
 ROOT_FS_IMG="${OUTPUT_DIR}/rootfs.image"
-MBR_IMG="${OUTPUT_DIR}/mbr.image"
 OUTPUT_IMG="${OUTPUT_DIR}/chromiumos_image.bin"
 
 BOARD="${FLAGS_board}"
@@ -323,7 +322,7 @@ fi
 # Extract the kernel from the root filesystem for use by the GPT image. Legacy
 # BIOS will use the kernel in the rootfs (via syslinux), ChromeOS BIOS will use
 # the kernel partition.
-sudo cp -f ${ROOT_FS_DIR}/boot/vmlinuz ${OUTPUT_DIR}/vmlinuz.image
+sudo cp -f "${ROOT_FS_DIR}/boot/vmlinuz" "${OUTPUT_DIR}/vmlinuz.image"
 
 #TODO(sosa@chromium.org) - Does it make sense to leave /usr/local bound here?
 "${SCRIPTS_DIR}/customize_rootfs" \
@@ -355,8 +354,11 @@ cleanup_rootfs_loop
 # Create the GPT-formatted image
 ${SCRIPTS_DIR}/build_gpt.sh \
    --arch=${ARCH} --board=${FLAGS_board} --board_root=${BOARD_ROOT} \
-   ${OUTPUT_DIR} ${OUTPUT_IMG}
+   "${OUTPUT_DIR}" "${OUTPUT_IMG}"
 
+# Clean up temporary files.
+rm -f "${ROOT_FS_IMG}" "${STATEFUL_IMG}" "${OUTPUT_DIR}/vmlinuz.image"
+rmdir "${ROOT_FS_DIR}" "${STATEFUL_DIR}"
 
 OUTSIDE_OUTPUT_DIR="../build/images/${FLAGS_board}/${IMAGE_SUBDIR}"
 echo "Done.  Image created in ${OUTPUT_DIR}"
diff --git a/emit_gpt_scripts.sh b/emit_gpt_scripts.sh
new file mode 100755
index 0000000000..4fea63d175
--- /dev/null
+++ b/emit_gpt_scripts.sh
@@ -0,0 +1,57 @@
+#!/bin/bash
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Emit scripts to pack and unpack the partitions from a GPT disk image.
+
+# Load common constants.  This should be the first executable line.
+# The path to common.sh should be relative to your script's location.
+. "$(dirname "$0")/common.sh"
+. "$(dirname "$0")/chromeos-common.sh"
+
+set -e
+
+# Usage
+IMAGE=${1:-}
+DIR=${2:-}
+if [[ -z "$IMAGE" || -z "$DIR" ]]; then
+  echo "Usage: $0 GPT_DEVICE DIRECTORY" 1>&2
+  exit 1
+fi
+
+PACK="${DIR}/pack_partitions.sh"
+UNPACK="${DIR}/unpack_partitions.sh"
+
+TMP=$(mktemp)
+sudo $GPT -r show -l "$IMAGE" > $TMP
+
+HEADER='#!/bin/sh -eu
+# File generated by emit_gpt_scripts.sh. Do not edit.
+TARGET=${1:-}
+if [[ -z "$TARGET" ]]; then
+  echo "Usage: $0 DEVICE" 1>&2
+  exit 1
+fi
+set -x'
+
+echo "$HEADER" > "$PACK"
+echo "$HEADER" > "$UNPACK"
+cat $TMP | sed -e 's/^/# /' >> "$PACK"
+cat $TMP | sed -e 's/^/# /' >> "$UNPACK"
+
+sort -n -k 3 $TMP | \
+  grep 'GPT part -' | \
+  while read start size part x x x label x; do \
+    file="part_$part"
+    loc="\"\$TARGET\""
+    echo "sudo dd if=$loc of=$file bs=512 skip=$start count=$size" \
+      >> "$UNPACK"
+    echo \
+      "sudo dd if=$file of=$loc bs=512 seek=$start count=$size conv=notrunc" \
+      >> "$PACK"
+  done
+
+chmod +x "$PACK" "$UNPACK"
+
+rm $TMP
diff --git a/image_to_usb.sh b/image_to_usb.sh
index 60ade0ccbd..b881e1a946 100755
--- a/image_to_usb.sh
+++ b/image_to_usb.sh
@@ -18,7 +18,7 @@ get_default_board
 # Flags
 DEFINE_string board "${DEFAULT_BOARD}" "Board for which the image was built"
 DEFINE_string from "" \
-  "Directory containing rootfs.image and mbr.image"
+  "Directory containing chromiumos_image.bin"
 DEFINE_string to "" "${DEFAULT_TO_HELP}"
 DEFINE_boolean yes ${FLAGS_FALSE} "Answer yes to all prompts" "y"
 DEFINE_boolean install_autotest ${FLAGS_FALSE} \
@@ -26,7 +26,7 @@ DEFINE_boolean install_autotest ${FLAGS_FALSE} \
 DEFINE_boolean copy_kernel ${FLAGS_FALSE} \
   "Copy the kernel to the fourth partition."
 DEFINE_boolean test_image "${FLAGS_FALSE}" \
-  "Uses test image if available, otherwise creates one as rootfs_test.image."
+  "Copies normal image to chromiumos_test_image.bin, modifies it for test."
 DEFINE_string build_root "/build" \
   "The root location for board sysroots."
 
@@ -100,12 +100,14 @@ if [ ${FLAGS_test_image} -eq ${FLAGS_TRUE} ] ; then
 fi
 
 STATEFUL_DIR="${FLAGS_from}/stateful_partition"
+mkdir -p "${STATEFUL_DIR}"
 
 function do_cleanup {
   echo "Cleaning loopback devices: ${STATEFUL_LOOP_DEV}"
   if [ "${STATEFUL_LOOP_DEV}" != "" ]; then
     sudo umount "${STATEFUL_DIR}"
     sudo losetup -d "${STATEFUL_LOOP_DEV}"
+    rmdir "${STATEFUL_DIR}"
     echo "Cleaned"
   fi
 }
@@ -144,6 +146,7 @@ if [ ${FLAGS_install_autotest} -eq ${FLAGS_TRUE} ] ; then
     sudo umount ${STATEFUL_DIR}
     sudo losetup -d "${stateful_loop_dev}"
     trap - INT TERM EXIT
+    rmdir "${STATEFUL_DIR}"
   else
     echo "/usr/local/autotest under ${DEFAULT_CHROOT_DIR} is not installed."
     echo "Please call make_autotest.sh inside chroot first."
diff --git a/mod_image_for_test.sh b/mod_image_for_test.sh
index c38fc92117..8d778e9d2f 100755
--- a/mod_image_for_test.sh
+++ b/mod_image_for_test.sh
@@ -75,6 +75,8 @@ cleanup() {
     cleanup_rootfs_loop
   fi
 
+  rmdir "${ROOT_FS_DIR}"
+
   # Turn die on error back on.
   set -e
 }
@@ -94,11 +96,12 @@ else
 fi
 
 set -e
-trap cleanup EXIT
 
 ROOT_FS_DIR=$(dirname "${FLAGS_image}")/rootfs
 mkdir -p "${ROOT_FS_DIR}"
 
+trap cleanup EXIT
+
 # Figure out how to loop mount the rootfs partition. It should be partition 3
 # on the disk image.
 offset=$(partoffset "${FLAGS_image}" 3)