diff --git a/scripts/unpack b/scripts/unpack
index c1b342a6ba..13caa3f883 100755
--- a/scripts/unpack
+++ b/scripts/unpack
@@ -38,6 +38,13 @@ STAMP=$STAMPS/$1/unpack
 
 [ -f "$STAMP" -a -f "$PKG_DIR/need_unpack" ] && $PKG_DIR/need_unpack $@
 
+# trigger unpack / full rebuild on any package.mk change
+if [ -f $PKG_DIR/package.mk ]; then
+  if [ -f $STAMP -a $PKG_DIR/package.mk -nt $STAMP ]; then
+    rm -f $STAMP
+  fi
+fi
+
 for patch in $PKG_DIR/patches/*; do
   if [ "$patch" -nt "$STAMP" ]; then
     rm -f $STAMP