diff --git a/core/net/rpl/rpl-conf.h b/core/net/rpl/rpl-conf.h
index 6822ff550..b86a36a85 100644
--- a/core/net/rpl/rpl-conf.h
+++ b/core/net/rpl/rpl-conf.h
@@ -242,7 +242,7 @@
 #ifdef RPL_CONF_WITH_DAO_ACK
 #define RPL_WITH_DAO_ACK RPL_CONF_WITH_DAO_ACK
 #else
-#define RPL_WITH_DAO_ACK 1
+#define RPL_WITH_DAO_ACK 0
 #endif /* RPL_CONF_WITH_DAO_ACK */
 
 /*
diff --git a/regression-tests/Makefile.simulation-test b/regression-tests/Makefile.simulation-test
index 58818c328..9995eeea8 100644
--- a/regression-tests/Makefile.simulation-test
+++ b/regression-tests/Makefile.simulation-test
@@ -31,7 +31,7 @@ TESTLOGS=$(patsubst %.csc,%.testlog,$(TESTS))
 LOGS=$(patsubst %.csc,%.log,$(TESTS))
 FAILLOGS=$(patsubst %.csc,%.*.faillog,$(TESTS))
 #Set random seeds to create reproduceable results.
-RANDOMSEED=1 5
+RANDOMSEED=1
 
 CONTIKI=../..