diff --git a/ArduCopter/sensors.pde b/ArduCopter/sensors.pde
index a80f80aa9d..3aed001f79 100644
--- a/ArduCopter/sensors.pde
+++ b/ArduCopter/sensors.pde
@@ -88,6 +88,8 @@ static void zero_airspeed(void)
 
 }
 
+#endif // HIL_MODE != HIL_MODE_ATTITUDE
+
 static void init_compass()
 {
 	compass.set_orientation(MAG_ORIENTATION);						// set compass's orientation on aircraft
@@ -110,8 +112,6 @@ static void init_optflow()
 #endif
 }
 
-#endif // HIL_MODE != HIL_MODE_ATTITUDE
-
 static void read_battery(void)
 {
 	battery_voltage1 = BATTERY_VOLTAGE(analogRead(BATTERY_PIN1)) * .1 + battery_voltage1 * .9;
diff --git a/libraries/AP_GPS/AP_GPS_Auto.cpp b/libraries/AP_GPS/AP_GPS_Auto.cpp
index b3a93b8a68..4eaa531a4b 100644
--- a/libraries/AP_GPS/AP_GPS_Auto.cpp
+++ b/libraries/AP_GPS/AP_GPS_Auto.cpp
@@ -99,6 +99,7 @@ AP_GPS_Auto::_detect(void)
     unsigned long then;
     int		fingerprint[4];
     int		tries;
+    int     charcount;
     GPS		*gps;
 
     //
@@ -114,15 +115,16 @@ AP_GPS_Auto::_detect(void)
         // XXX We can detect babble by counting incoming characters, but
         //     what would we do about it?
         //
+        charcount = 0;
         _port->flush();
         then = millis();
         do {
-            callback(1);
             if (_port->available()) {
                 then = millis();
                 _port->read();
+                charcount++;
             }
-        } while ((millis() - then) < 50);
+        } while ((millis() - then) < 50 && charcount < 5000);
 
         //
         // Collect four characters to fingerprint a device