diff --git a/C/iopreds.c b/C/iopreds.c
index 7a319580e..87a424d28 100644
--- a/C/iopreds.c
+++ b/C/iopreds.c
@@ -3977,7 +3977,8 @@ static Int
 	  Yap_clean_tokenizer(tokstart, Yap_VarTable, Yap_AnonVarTable);
 	
 	  return Yap_unify(tpos,ARG5) &&
-	    Yap_unify_constant(ARG2, MkAtomTerm (AtomEof));
+	    Yap_unify_constant(ARG2, MkAtomTerm (AtomEof))
+	    && Yap_unify_constant(ARG4, TermNil);
 	}
       }
     }
diff --git a/C/tracer.c b/C/tracer.c
index 4b91937ed..0ebba4ee4 100644
--- a/C/tracer.c
+++ b/C/tracer.c
@@ -172,6 +172,8 @@ low_level_trace(yap_low_level_port port, PredEntry *pred, CELL *args)
   LOCK(Yap_heap_regs->low_level_trace_lock);
   sc = Yap_heap_regs;
   vsc_count++;
+  if (vsc_count < 3630000LL)
+    return;
 #ifdef THREADS
   Yap_heap_regs->thread_handle[worker_id].thread_inst_count++;
 #endif