diff --git a/example/hfp_hf_demo.c b/example/hfp_hf_demo.c
index 406d78232..ea367250e 100644
--- a/example/hfp_hf_demo.c
+++ b/example/hfp_hf_demo.c
@@ -489,8 +489,7 @@ static void packet_handler(uint8_t packet_type, uint16_t channel, uint8_t * even
                                 printf("Audio connection establishment failed with status %u\n", hfp_subevent_audio_connection_established_get_status(event));
                             } else {
                                 sco_handle = hfp_subevent_audio_connection_established_get_handle(event);
-                                negotiated_codec = hfp_subevent_audio_connection_established_get_negotiated_codec(event);
-                                printf("Audio connection established with SCO handle 0x%04x and codec 0x%02x.\n", sco_handle, negotiated_codec);
+                                printf("Audio connection established with SCO handle 0x%04x.\n", sco_handle);
                                 hci_request_sco_can_send_now_event();
                             }
                             break;
diff --git a/src/btstack_defines.h b/src/btstack_defines.h
index 63d31ed55..e92c55ced 100644
--- a/src/btstack_defines.h
+++ b/src/btstack_defines.h
@@ -920,7 +920,6 @@ typedef uint8_t sm_key_t[16];
  * @param status 0 == OK
  * @param con_handle
  * @param bd_addr
- * @param negotiated_codec
  */
 #define HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_ESTABLISHED  0x01
 
@@ -936,7 +935,6 @@ typedef uint8_t sm_key_t[16];
  * @param status 0 == OK
  * @param handle
  * @param bd_addr
- * @param negotiated_codec
  */
 #define HFP_SUBEVENT_AUDIO_CONNECTION_ESTABLISHED          0x03
 
diff --git a/src/btstack_event.h b/src/btstack_event.h
index 9c55f88fe..ed89d4d22 100644
--- a/src/btstack_event.h
+++ b/src/btstack_event.h
@@ -2748,15 +2748,6 @@ static inline hci_con_handle_t hfp_subevent_service_level_connection_established
 static inline void hfp_subevent_service_level_connection_established_get_bd_addr(const uint8_t * event, bd_addr_t bd_addr){
     reverse_bd_addr(&event[6], bd_addr);    
 }
-/**
- * @brief Get field negotiated_codec from event HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_ESTABLISHED
- * @param event packet
- * @return negotiated_codec
- * @note: btstack_type 1
- */
-static inline uint8_t hfp_subevent_service_level_connection_established_get_negotiated_codec(const uint8_t * event){
-    return event[12];
-}
 
 
 /**
@@ -2786,15 +2777,6 @@ static inline hci_con_handle_t hfp_subevent_audio_connection_established_get_han
 static inline void hfp_subevent_audio_connection_established_get_bd_addr(const uint8_t * event, bd_addr_t bd_addr){
     reverse_bd_addr(&event[6], bd_addr);    
 }
-/**
- * @brief Get field negotiated_codec from event HFP_SUBEVENT_AUDIO_CONNECTION_ESTABLISHED
- * @param event packet
- * @return negotiated_codec
- * @note: btstack_type 1
- */
-static inline uint8_t hfp_subevent_audio_connection_established_get_negotiated_codec(const uint8_t * event){
-    return event[12];
-}
 
 
 /**
diff --git a/src/classic/hfp.c b/src/classic/hfp.c
index 246c5b6eb..af4994bfe 100644
--- a/src/classic/hfp.c
+++ b/src/classic/hfp.c
@@ -224,9 +224,9 @@ void hfp_emit_event(btstack_packet_handler_t callback, uint8_t event_subtype, ui
     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
 }
 
-void hfp_emit_connection_event(btstack_packet_handler_t callback, uint8_t event_subtype, uint8_t status, hci_con_handle_t con_handle, bd_addr_t addr, uint8_t codec){
+void hfp_emit_connection_event(btstack_packet_handler_t callback, uint8_t event_subtype, uint8_t status, hci_con_handle_t con_handle, bd_addr_t addr){
     if (!callback) return;
-    uint8_t event[13];
+    uint8_t event[12];
     int pos = 0;
     event[pos++] = HCI_EVENT_HFP_META;
     event[pos++] = sizeof(event) - 2;
@@ -236,7 +236,6 @@ void hfp_emit_connection_event(btstack_packet_handler_t callback, uint8_t event_
     pos += 2;
     reverse_bd_addr(addr,&event[pos]);
     pos += 6;
-    event[pos] = codec;
     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
 }
 
@@ -530,7 +529,7 @@ void hfp_handle_hci_event(uint8_t packet_type, uint16_t channel, uint8_t *packet
             if (!hfp_connection || hfp_connection->state != HFP_W4_RFCOMM_CONNECTED) return;
 
             if (status) {
-                hfp_emit_connection_event(hfp_callback, HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_ESTABLISHED, status, rfcomm_event_channel_opened_get_con_handle(packet), event_addr, hfp_connection->negotiated_codec);
+                hfp_emit_connection_event(hfp_callback, HFP_SUBEVENT_SERVICE_LEVEL_CONNECTION_ESTABLISHED, status, rfcomm_event_channel_opened_get_con_handle(packet), event_addr);
                 remove_hfp_connection_context(hfp_connection);
             } else {
                 hfp_connection->acl_handle = rfcomm_event_channel_opened_get_con_handle(packet);
@@ -623,7 +622,7 @@ void hfp_handle_hci_event(uint8_t packet_type, uint16_t channel, uint8_t *packet
             hfp_connection->sco_handle = sco_handle;
             hfp_connection->establish_audio_connection = 0;
             hfp_connection->state = HFP_AUDIO_CONNECTION_ESTABLISHED;
-            hfp_emit_connection_event(hfp_callback, HFP_SUBEVENT_AUDIO_CONNECTION_ESTABLISHED, packet[2], sco_handle, event_addr, hfp_connection->negotiated_codec);
+            hfp_emit_connection_event(hfp_callback, HFP_SUBEVENT_AUDIO_CONNECTION_ESTABLISHED, packet[2], sco_handle, event_addr);
             break;                
         }
 
diff --git a/src/classic/hfp.h b/src/classic/hfp.h
index 51e760f7c..4c44d6cec 100644
--- a/src/classic/hfp.h
+++ b/src/classic/hfp.h
@@ -628,7 +628,7 @@ void hfp_handle_hci_event(uint8_t packet_type, uint16_t channel, uint8_t *packet
 void hfp_emit_event(btstack_packet_handler_t callback, uint8_t event_subtype, uint8_t value);
 void hfp_emit_simple_event(btstack_packet_handler_t callback, uint8_t event_subtype);
 void hfp_emit_string_event(btstack_packet_handler_t callback, uint8_t event_subtype, const char * value);
-void hfp_emit_connection_event(btstack_packet_handler_t callback, uint8_t event_subtype, uint8_t status, hci_con_handle_t con_handle, bd_addr_t addr, uint8_t codec);
+void hfp_emit_connection_event(btstack_packet_handler_t callback, uint8_t event_subtype, uint8_t status, hci_con_handle_t con_handle, bd_addr_t addr);
 void hfp_emit_codec_event(btstack_packet_handler_t callback, uint8_t status, uint8_t codec);
 
 hfp_connection_t * get_hfp_connection_context_for_rfcomm_cid(uint16_t cid);