diff --git a/tests/scripts/thread-cert/Cert_5_5_08_SplitRoutersLostLeader.py b/tests/scripts/thread-cert/Cert_5_5_08_SplitRoutersLostLeader.py
index bc5224362..b51c4f57c 100755
--- a/tests/scripts/thread-cert/Cert_5_5_08_SplitRoutersLostLeader.py
+++ b/tests/scripts/thread-cert/Cert_5_5_08_SplitRoutersLostLeader.py
@@ -48,6 +48,7 @@ class Cert_5_5_8_SplitRoutersLostLeader(unittest.TestCase):
         self.nodes[LEADER1].set_mode('rsdn')
         self.nodes[LEADER1].add_whitelist(self.nodes[ROUTER3].get_addr64())
         self.nodes[LEADER1].enable_whitelist()
+        self.nodes[LEADER1].set_router_selection_jitter(1)
 
         self.nodes[ROUTER3].set_panid(0xface)
         self.nodes[ROUTER3].set_mode('rsdn')