diff --git a/ArduCopter/Log.pde b/ArduCopter/Log.pde
index 387f2c5406..2eae50f724 100644
--- a/ArduCopter/Log.pde
+++ b/ArduCopter/Log.pde
@@ -1314,7 +1314,7 @@ static void Log_Write_Mode(uint8_t mode) {
 }
 static void Log_Write_Raw() {
 }
-void print_latlon(BetterStream *s, int32_t lat_or_lon) {
+void print_latlon(AP_HAL::BetterStream *s, int32_t lat_or_lon) {
 }
 static void Log_Write_GPS() {
 }
diff --git a/ArduCopter/sensors.pde b/ArduCopter/sensors.pde
index 607c99a676..9ffffc56c4 100644
--- a/ArduCopter/sensors.pde
+++ b/ArduCopter/sensors.pde
@@ -35,9 +35,9 @@ static int32_t read_barometer(void)
 static int16_t read_sonar(void)
 {
 #if CONFIG_SONAR == ENABLED
-    int16_t temp_alt = sonar.read();
+    int16_t temp_alt = sonar->read();
 
-    if(temp_alt >= sonar.min_distance && temp_alt <= sonar.max_distance * 0.70) {
+    if(temp_alt >= sonar->min_distance && temp_alt <= sonar->max_distance * 0.70) {
         sonar_alt_ok = true;
     }else{
         sonar_alt_ok = false;
diff --git a/ArduCopter/system.pde b/ArduCopter/system.pde
index ec620370b4..f3ac9f2bd1 100644
--- a/ArduCopter/system.pde
+++ b/ArduCopter/system.pde
@@ -292,8 +292,8 @@ init_rate_controllers();
 // Experimental AP_Limits library - set constraints, limits, fences, minima,
 // maxima on various parameters
 ////////////////////////////////////////////////////////////////////////////////
+static void init_ap_limits() {
 #if AP_LIMITS == ENABLED
-
     // The linked list looks (logically) like this [limits module] -> [first
     // limit module] -> [second limit module] -> [third limit module] -> NULL