diff --git a/dcs.c b/dcs.c
index 73a371c0..3f412507 100644
--- a/dcs.c
+++ b/dcs.c
@@ -8,19 +8,21 @@
 static void
 bsu(struct terminal *term)
 {
-    LOG_DBG("BSU - Begin Synchronized Update (params: %.*s)",
+    LOG_WARN("untested: BSU - Begin Synchronized Update (params: %.*s)",
             (int)term->vt.dcs.idx, term->vt.dcs.data);
 
     term_enable_application_synchronized_updates(term);
+    abort();
 }
 
 static void
 esu(struct terminal *term)
 {
-    LOG_DBG("ESU - Begin Synchronized Update (params: %.*s)",
+    LOG_WARN("untested: ESU - Begin Synchronized Update (params: %.*s)",
             (int)term->vt.dcs.idx, term->vt.dcs.data);
 
     term_disable_application_synchronized_updates(term);
+    abort();
 }
 
 void