diff --git a/config/functions b/config/functions
index 5384cb9486..89bd8e5ec0 100644
--- a/config/functions
+++ b/config/functions
@@ -752,11 +752,16 @@ get_pkg_directory() {
 }
 
 calculate_stamp() {
-  local stamp
+  local stamp data
+
   stamp="$PKG_DIR $PROJECT_DIR/$PROJECT/patches/$PKG_NAME"
   [ -n "$DEVICE" ] && stamp+=" $PROJECT_DIR/$PROJECT/devices/$DEVICE/patches/$PKG_NAME"
   [ -n "$PKG_NEED_UNPACK" ] && stamp+=" $PKG_NEED_UNPACK"
-  find ${stamp} -exec sha256sum {} \; 2>/dev/null | sed "s/ ${ROOT//\//\\/}\// /" | sort | sha256sum | cut -d" " -f1
+
+  data="$(find ${stamp} -exec sha256sum {} \; 2>/dev/null | sed "s/ ${ROOT//\//\\/}\// /")"
+  [ -n "${PKG_STAMP}" ] && data+=$'\n'"$(echo "${PKG_STAMP}" | sha256sum)"
+
+  echo "${data}" | sort | sha256sum | cut -d" " -f1
 }
 
 target_has_feature() {