Don't reboot the system when serial port is not detected properly

Change-Id: I3e691166d67d528365710cdb25ad64888a565b85
diff --git a/edge-monitoring/agent_modem/edge-mon-agent.service b/edge-monitoring/agent_modem/edge-mon-agent.service
index c7c4d50..8f80c05 100644
--- a/edge-monitoring/agent_modem/edge-mon-agent.service
+++ b/edge-monitoring/agent_modem/edge-mon-agent.service
@@ -7,6 +7,7 @@
 Type=simple
 ExecStart=/home/pi/Aether/aether-monitoring/edge-monitoring/agent_modem/edge_monitoring_agent_modem.py
 Restart=on-failure
+ExecStartPre=/bin/sleep 5
 
 [Install]
 WantedBy=multi-user.target
diff --git a/edge-monitoring/agent_modem/edge_monitoring_agent_modem.py b/edge-monitoring/agent_modem/edge_monitoring_agent_modem.py
index 1ab69fe..a9a89f0 100755
--- a/edge-monitoring/agent_modem/edge_monitoring_agent_modem.py
+++ b/edge-monitoring/agent_modem/edge_monitoring_agent_modem.py
@@ -156,7 +156,7 @@
 
     # Give 10 sec for the modem to be fully connected
     retry = 0
-    while retry < 10:
+    while retry < 30:
         state = modem.is_connected()
         if state is State.connected:
             break
@@ -198,7 +198,7 @@
         modem.connect()
     except serial.serialutil.SerialException as e:
         logging.error("Failed to connect the modem for %s", e)
-        os.system("sudo shutdown -r now")
+        sys.exit(1)
 
     success = os.system("sudo ip route replace {}/32 via {}".format(
         CONF.ping_to, CONF.modem.ip_addr))