diff --git a/libraries/AP_NavEKF2/AP_NavEKF2.cpp b/libraries/AP_NavEKF2/AP_NavEKF2.cpp
index c62dcd3806..ad30bee0b1 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2.cpp
@@ -663,7 +663,7 @@ bool NavEKF2::InitialiseFilter(void)
 
     // zero the structs used capture reset events
     memset(&yaw_reset_data, 0, sizeof(yaw_reset_data));
-    memset(&pos_reset_data, 0, sizeof(pos_reset_data));
+    memset((void *)&pos_reset_data, 0, sizeof(pos_reset_data));
     memset(&pos_down_reset_data, 0, sizeof(pos_down_reset_data));
 
     check_log_write();
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_Buffer.h b/libraries/AP_NavEKF2/AP_NavEKF2_Buffer.h
index 938f93a351..6fba6bdf5e 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_Buffer.h
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_Buffer.h
@@ -19,7 +19,7 @@ public:
         {
             return false;
         }
-        memset(buffer,0,size*sizeof(element_t));
+        memset((void *)buffer,0,size*sizeof(element_t));
         _size = size;
         _head = 0;
         _tail = 0;
@@ -103,7 +103,7 @@ public:
         _head = 0;
         _tail = 0;
         _new_data = false;
-        memset(buffer,0,_size*sizeof(element_t));
+        memset((void *)buffer,0,_size*sizeof(element_t));
     }
 
 private:
@@ -130,7 +130,7 @@ public:
         {
             return false;
         }
-        memset(buffer,0,size*sizeof(element_t));
+        memset((void *)buffer,0,size*sizeof(element_t));
         _size = size;
         _youngest = 0;
         _oldest = 0;
@@ -173,7 +173,7 @@ public:
     inline void reset() {
         _youngest = 0;
         _oldest = 0;
-        memset(buffer,0,_size*sizeof(element_t));
+        memset((void *)buffer,0,_size*sizeof(element_t));
     }
 
     // retrieves data from the ring buffer at a specified index
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
index 1fd2016384..f5fd0ada21 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
@@ -258,8 +258,8 @@ void NavEKF2_core::InitialiseVariables()
     memset(&velPosObs, 0, sizeof(velPosObs));
 
     // range beacon fusion variables
-    memset(&rngBcnDataNew, 0, sizeof(rngBcnDataNew));
-    memset(&rngBcnDataDelayed, 0, sizeof(rngBcnDataDelayed));
+    memset((void *)&rngBcnDataNew, 0, sizeof(rngBcnDataNew));
+    memset((void *)&rngBcnDataDelayed, 0, sizeof(rngBcnDataDelayed));
     rngBcnStoreIndex = 0;
     lastRngBcnPassTime_ms = 0;
     rngBcnTestRatio = 0.0f;
@@ -297,8 +297,8 @@ void NavEKF2_core::InitialiseVariables()
     last_gps_idx = 0;
 
     // external nav data fusion
-    memset(&extNavDataNew, 0, sizeof(extNavDataNew));
-    memset(&extNavDataDelayed, 0, sizeof(extNavDataDelayed));
+    memset((void *)&extNavDataNew, 0, sizeof(extNavDataNew));
+    memset((void *)&extNavDataDelayed, 0, sizeof(extNavDataDelayed));
     extNavDataToFuse = false;
     extNavMeasTime_ms = 0;
     extNavLastPosResetTime_ms = 0;