diff --git a/build_image b/build_image
index 697c109cee..16f5d70622 100755
--- a/build_image
+++ b/build_image
@@ -108,11 +108,13 @@ fi
 PROD_IMAGE=0
 PROD_TAR=0
 CONTAINER=0
+SYSEXT=0
 for arg in "$@"; do
   case "${arg}" in
     prod) PROD_IMAGE=1 ;;
     prodtar) PROD_IMAGE=1 PROD_TAR=1 ;;
     container) CONTAINER=1 ;;
+    sysext) SYSEXT=1 ;;
     *)    die_notrace "Unknown image type ${arg}" ;;
   esac
 done
@@ -177,6 +179,9 @@ if [[ "${PROD_IMAGE}" -eq 1 ]]; then
     create_prod_tar ${FLATCAR_PRODUCTION_IMAGE_NAME}
   fi
 fi
+if [[ "${SYSEXT}" -eq 1 ]]; then
+  create_prod_sysexts "${FLATCAR_PRODUCTION_IMAGE_NAME}"
+fi
 
 if [[ ${FLAGS_generate_update} -eq ${FLAGS_TRUE} ]] || \
    [[ ${FLAGS_extract_update} -eq ${FLAGS_TRUE} ]]
diff --git a/build_library/prod_image_util.sh b/build_library/prod_image_util.sh
index 1f8029dc8c..02c0571d09 100755
--- a/build_library/prod_image_util.sh
+++ b/build_library/prod_image_util.sh
@@ -247,3 +247,42 @@ create_prod_tar() {
   sudo losetup --detach "${lodev}"
   upload_image "${container}"
 }
+
+EXTRA_SYSEXTS=(
+  zfs:sys-fs/zfs
+)
+
+create_prod_sysexts() {
+  local image_name="$1"
+  local image_sysext_base="${image_name%.bin}_sysext.squashfs"
+  sudo rm -rf "${BUILD_DIR}/sysexts/*"
+  mkdir -p "${BUILD_DIR}/sysexts"
+  local to_upload=()
+  for sysext in "${EXTRA_SYSEXTS[@]}"; do
+    local name="flatcar-${sysext%:*}"
+    local pkg="${sysext#*:}"
+    local mangle_script="${BUILD_LIBRARY_DIR}/sysext_mangle_${name}"
+    if [[ ! -x "${mangle_script}" ]]; then
+      mangle_script=
+    fi
+    sudo "${SCRIPT_ROOT}/build_sysext" --board="${BOARD}" \
+        --squashfs_base="${BUILD_DIR}/${image_sysext_base}" \
+	--image_builddir="${BUILD_DIR}/sysexts" \
+	${mangle_script:+--manglefs_script=${mangle_script}} \
+	"${name}" "${pkg}"
+    delta_generator \
+      -private_key "/usr/share/update_engine/update-payload-key.key.pem" \
+      -new_image "${BUILD_DIR}/sysexts/${name}.raw" \
+      -out_file "${BUILD_DIR}/sysexts/flatcar_test_update-${name}.gz"
+    to_upload+=(
+        "${BUILD_DIR}/sysexts/${name}.raw"
+        "${BUILD_DIR}/sysexts/${name}_contents.txt"
+        "${BUILD_DIR}/sysexts/${name}_contents_wtd.txt"
+        "${BUILD_DIR}/sysexts/${name}_disk_usage.txt"
+        "${BUILD_DIR}/sysexts/${name}_packages.txt"
+        "${BUILD_DIR}/sysexts/flatcar_test_update-${name}.gz"
+    )
+  done
+  upload_image -d ${BUILD_DIR}/sysexts/sysext.DIGESTS "${to_upload[@]}"
+}
+