diff --git a/poky/meta/classes/rootfs-postcommands.bbclass b/poky/meta/classes/rootfs-postcommands.bbclass
index 74035c3..cd8986d 100644
--- a/poky/meta/classes/rootfs-postcommands.bbclass
+++ b/poky/meta/classes/rootfs-postcommands.bbclass
@@ -380,7 +380,7 @@
     from oe.overlayfs import mountUnitName
 
     # this is a dumb check for unit existence, not its validity
-    overlayMountPoints = d.getVarFlags("OVERLAYFS_MOUNT_POINT")
+    overlayMountPoints = d.getVarFlags("OVERLAYFS_MOUNT_POINT") or {}
     imagepath = d.getVar("IMAGE_ROOTFS")
     searchpaths = [oe.path.join(imagepath, d.getVar("sysconfdir"), "systemd", "system"),
                    oe.path.join(imagepath, d.getVar("systemd_system_unitdir"))]