diff --git a/make_factory_package.sh b/make_factory_package.sh
index a862606837..9f059ee37c 100755
--- a/make_factory_package.sh
+++ b/make_factory_package.sh
@@ -474,40 +474,41 @@ generate_omaha() {
   echo "Output omaha config to ${OMAHA_CONF}"
 
   # Get the release image.
-  ( set -e
-    cd "${RELEASE_DIR}"
-    prepare_dir "."
+  # TODO(hungte) deprecate pushd and use temporary folders
+  pushd "${RELEASE_DIR}" >/dev/null
+  prepare_dir "."
 
-    kernel="${RELEASE_KERNEL:-${RELEASE_IMAGE}:2}"
-    rootfs="${RELEASE_IMAGE}:3"
-    release_hash="$(compress_and_hash_memento_image "$kernel" "$rootfs")"
-    mv ./update.gz "${OMAHA_DATA_DIR}/rootfs-release.gz"
-    echo "release: ${release_hash}"
+  kernel="${RELEASE_KERNEL:-${RELEASE_IMAGE}:2}"
+  rootfs="${RELEASE_IMAGE}:3"
+  release_hash="$(compress_and_hash_memento_image "$kernel" "$rootfs")"
+  mv ./update.gz "${OMAHA_DATA_DIR}/rootfs-release.gz"
+  echo "release: ${release_hash}"
 
-    oem_hash="$(compress_and_hash_partition "${RELEASE_IMAGE}" 8 "oem.gz")"
-    mv oem.gz "${OMAHA_DATA_DIR}"
-    echo "oem: ${oem_hash}"
-  )
+  oem_hash="$(compress_and_hash_partition "${RELEASE_IMAGE}" 8 "oem.gz")"
+  mv oem.gz "${OMAHA_DATA_DIR}"
+  echo "oem: ${oem_hash}"
+
+  popd >/dev/null
 
   # Go to retrieve the factory test image.
-  ( set -e
-    cd "${FACTORY_DIR}"
-    prepare_dir "."
+  pushd "${FACTORY_DIR}" >/dev/null
+  prepare_dir "."
 
-    kernel="${FACTORY_IMAGE}:2"
-    rootfs="${FACTORY_IMAGE}:3"
-    test_hash="$(compress_and_hash_memento_image "$kernel" "$rootfs")"
-    mv ./update.gz "${OMAHA_DATA_DIR}/rootfs-test.gz"
-    echo "test: ${test_hash}"
+  kernel="${FACTORY_IMAGE}:2"
+  rootfs="${FACTORY_IMAGE}:3"
+  test_hash="$(compress_and_hash_memento_image "$kernel" "$rootfs")"
+  mv ./update.gz "${OMAHA_DATA_DIR}/rootfs-test.gz"
+  echo "test: ${test_hash}"
 
-    state_hash="$(compress_and_hash_partition "${FACTORY_IMAGE}" 1 "state.gz")"
-    mv state.gz "${OMAHA_DATA_DIR}"
-    echo "state: ${state_hash}"
+  state_hash="$(compress_and_hash_partition "${FACTORY_IMAGE}" 1 "state.gz")"
+  mv state.gz "${OMAHA_DATA_DIR}"
+  echo "state: ${state_hash}"
 
-    efi_hash="$(compress_and_hash_partition "${FACTORY_IMAGE}" 12 "efi.gz")"
-    mv efi.gz "${OMAHA_DATA_DIR}"
-    echo "efi: ${efi_hash}"
-  )
+  efi_hash="$(compress_and_hash_partition "${FACTORY_IMAGE}" 12 "efi.gz")"
+  mv efi.gz "${OMAHA_DATA_DIR}"
+  echo "efi: ${efi_hash}"
+
+  popd >/dev/null
 
   if [ -n "${FLAGS_firmware_updater}" ]; then
     firmware_hash="$(compress_and_hash_file "${FLAGS_firmware_updater}" \