diff --git a/NetworkSync.cpp b/NetworkSync.cpp
index 4142fea..30b4a06 100644
--- a/NetworkSync.cpp
+++ b/NetworkSync.cpp
@@ -9,11 +9,14 @@
 #include "LinearAlgebra/Angle8.h"
 #include "LinearAlgebra/Spherical.h"
 
-void NetworkSync::SendVector3(unsigned char *data, unsigned int startIndex,
+void NetworkSync::SendVector3(unsigned char *data, unsigned char *startIndex,
                               const Vector3 v) {
-  SendSingle100(data, startIndex, v.x);
-  SendSingle100(data, startIndex += 4, v.y);
-  SendSingle100(data, startIndex += 4, v.z);
+  SendSingle100(data, *startIndex, v.x);
+  (*startIndex) += 4;
+  SendSingle100(data, *startIndex, v.y);
+  (*startIndex) += 4;
+  SendSingle100(data, *startIndex, v.z);
+  (*startIndex) += 4;
 }
 
 void NetworkSync::SendQuaternion(unsigned char *data, const int startIndex,
@@ -52,7 +55,7 @@ void NetworkSync::SendSpherical(unsigned char *data, int startIndex,
 //   SendSingle100(data, startIndex += 4, s.distance);
 // }
 
-void NetworkSync::SendQuat32(unsigned char *data, int startIndex,
+void NetworkSync::SendQuat32(unsigned char *data, unsigned char *startIndex,
                              const Quaternion q) {
   unsigned char qx = (char)(q.x * 127 + 128);
   unsigned char qy = (char)(q.y * 127 + 128);
@@ -65,10 +68,10 @@ void NetworkSync::SendQuat32(unsigned char *data, int startIndex,
     qw = -qw;
   }
   // Serial.printf(" (%d) %d:%d:%d:%d ", startIndex, qx, qy, qz, qw);
-  data[startIndex++] = qx;
-  data[startIndex++] = qy;
-  data[startIndex++] = qz;
-  data[startIndex++] = qw;
+  data[(*startIndex)++] = qx;
+  data[(*startIndex)++] = qy;
+  data[(*startIndex)++] = qz;
+  data[(*startIndex)++] = qw;
 }
 
 void NetworkSync::SendAngle8(unsigned char *data, unsigned int startIndex,
diff --git a/NetworkSync.h b/NetworkSync.h
index 9368d06..096c5b7 100644
--- a/NetworkSync.h
+++ b/NetworkSync.h
@@ -62,7 +62,7 @@ protected:
   //                  const float value);
   // void SendAngle32(unsigned char *data, unsigned int startIndex,
   //                  const float value);
-  void SendVector3(unsigned char *data, unsigned int startIndex,
+  void SendVector3(unsigned char *data, unsigned char *startIndex,
                    const Vector3 v);
   void SendQuaternion(unsigned char *data, const int startIndex,
                       const Quaternion q);
@@ -71,7 +71,8 @@ protected:
   void SendSpherical(unsigned char *data, int startIndex, Spherical s);
   // void SendSpherical16(unsigned char *data, int startIndex, Spherical s);
   // void SendSpherical32(unsigned char *data, int startIndex, Spherical s);
-  void SendQuat32(unsigned char *data, int startIndex, const Quaternion q);
+  void SendQuat32(unsigned char *data, unsigned char *startIndex,
+                  const Quaternion q);
 };
 
 } // namespace RoboidControl