Modify customize_rootfs.sh to run outside of the target rootfs and to use

src/scripts/build_image.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 build a bootable keyfob-based chromeos system image.
 # It uses debootstrap (see https://wiki.ubuntu.com/DebootstrapChroot) to
 # create a base file system. It then cusotmizes the file system and adds
 # Ubuntu and chromeos specific packages. Finally, it creates a bootable USB
@@ skipping 166 matching lines @@
 # Set up bind mount for trunk, so we can get to package repository
 # TODO: also use this instead of SETUP_DIR for other things below?
 sudo mkdir -p "$ROOT_FS_DIR/trunk"
 sudo mount --bind "$GCLIENT_ROOT" "$ROOT_FS_DIR/trunk"
 
 # Create setup directory and copy over scripts, config files, and locally
 # built packages.
 mkdir -p "$SETUP_DIR"
 mkdir -p "${SETUP_DIR}/local_packages"
 cp "${SCRIPTS_DIR}/${ROOTFS_PACKAGE_INSTALL_SCRIPT}" "$SETUP_DIR"
-cp "${SCRIPTS_DIR}/${ROOTFS_CUSTOMIZE_SCRIPT}" "$SETUP_DIR"
 cp -r "$ROOTFS_STATIC_DATA" "$SETUP_DIR"
 cp "$FLAGS_pkglist" "${SETUP_DIR}/package-list-prod.txt"
 cp "${FLAGS_build_root}/x86/local_packages"/* "${SETUP_DIR}/local_packages"
 
 if [ -n "$FLAGS_pkglist2" ]
 then
   cp "$FLAGS_pkglist2" "${SETUP_DIR}/package-list-2.txt"
 fi
 
 # Set up repository for local packages to install in the rootfs via apt-get.
@@ skipping 19 matching lines @@
 SUITE2="$FLAGS_suite2"
 EOF
 # ...and all CHROMEOS_ vars
 set | egrep "^CHROMEOS_|^BUILDBOT_" >> $CUST_OPTS
 
 # Run the package install script
 sudo chroot "$ROOT_FS_DIR" \
   "${ROOTFS_SETUP_DIR}/${ROOTFS_PACKAGE_INSTALL_SCRIPT}"
 
 # Run the script to customize the resulting root file system.
-sudo chroot "$ROOT_FS_DIR" "${ROOTFS_SETUP_DIR}/${ROOTFS_CUSTOMIZE_SCRIPT}"
+"${SCRIPTS_DIR}/${ROOTFS_CUSTOMIZE_SCRIPT}" --root="${ROOT_FS_DIR}"
 
 # No longer need the setup directory in the rootfs.
 rm -rf "$SETUP_DIR"
 
 # Move package lists from the image into the output dir
 sudo mv "$ROOT_FS_DIR"/etc/package_list_*.txt "$OUTPUT_DIR"
 
 # Unmount mounts within the rootfs so it is ready to be imaged.
 cleanup_rootfs_mounts
 
@@ skipping 38 matching lines @@
 EOF
 
 OUTSIDE_OUTPUT_DIR="${EXTERNAL_TRUNK_PATH}/src/build/images/${IMAGE_SUBDIR}"
 echo "Done.  Image created in ${OUTPUT_DIR}"
 echo "To copy to USB keyfob, outside the chroot, do something like:"
 echo "  ./image_to_usb.sh --from=${OUTSIDE_OUTPUT_DIR} --to=/dev/sdb"
 echo "To convert to VMWare image, outside the chroot, do something like:"
 echo "  ./image_to_vmware.sh --from=${OUTSIDE_OUTPUT_DIR}"
 
 trap - EXIT