diff --git a/src/utility/HCI.cpp b/src/utility/HCI.cpp
index 51366db3..e0019640 100644
--- a/src/utility/HCI.cpp
+++ b/src/utility/HCI.cpp
@@ -413,7 +413,7 @@ int HCIClass::leConnUpdate(uint16_t handle, uint16_t minInterval, uint16_t maxIn
   return sendCommand(OGF_LE_CTL << 10 | OCF_LE_CONN_UPDATE, sizeof(leConnUpdateData), &leConnUpdateData);
 }
 
-int HCIClass::sendAclPkt(uint16_t handle, uint8_t cid, uint8_t plen, void* data)
+int HCIClass::sendAclPkt(uint16_t handle, uint8_t cid, uint8_t plen, const void* data)
 {
   while (_pendingPkt >= _maxPkt) {
     poll();
@@ -462,7 +462,7 @@ void HCIClass::noDebug()
   _debug = NULL;
 }
 
-int HCIClass::sendCommand(uint16_t opcode, uint8_t plen, void* parameters)
+int HCIClass::sendCommand(uint16_t opcode, uint8_t plen, const void* parameters)
 {
   struct __attribute__ ((packed)) {
     uint8_t pktType;
diff --git a/src/utility/HCI.h b/src/utility/HCI.h
index 6d6b69ee..d33f6e9e 100644
--- a/src/utility/HCI.h
+++ b/src/utility/HCI.h
@@ -64,7 +64,7 @@ class HCIClass {
   virtual int leCancelConn();
 
 
-  virtual int sendAclPkt(uint16_t handle, uint8_t cid, uint8_t plen, void* data);
+  virtual int sendAclPkt(uint16_t handle, uint8_t cid, uint8_t plen, const void* data);
 
   virtual int disconnect(uint16_t handle);
 
@@ -72,7 +72,7 @@ class HCIClass {
   virtual void noDebug();
 
 private:
-  virtual int sendCommand(uint16_t opcode, uint8_t plen = 0, void* parameters = NULL);
+  virtual int sendCommand(uint16_t opcode, uint8_t plen = 0, const void* parameters = nullptr);
 
   virtual void handleAclDataPkt(uint8_t plen, uint8_t pdata[]);
   virtual void handleNumCompPkts(uint16_t handle, uint16_t numPkts);