diff --git a/poky/meta/classes/image-combined-dbg.bbclass b/poky/meta/classes/image-combined-dbg.bbclass
index f4772f7..e5dc61f 100644
--- a/poky/meta/classes/image-combined-dbg.bbclass
+++ b/poky/meta/classes/image-combined-dbg.bbclass
@@ -1,4 +1,4 @@
-IMAGE_PREPROCESS_COMMAND_append = " combine_dbg_image; "
+IMAGE_PREPROCESS_COMMAND:append = " combine_dbg_image; "
 
 combine_dbg_image () {
         if [ "${IMAGE_GEN_DEBUGFS}" = "1" -a -e ${IMAGE_ROOTFS}-dbg ]; then