diff --git a/src/classic/hfp_codec.c b/src/classic/hfp_codec.c
index 81f6ae11a..f9b4c672c 100644
--- a/src/classic/hfp_codec.c
+++ b/src/classic/hfp_codec.c
@@ -90,6 +90,7 @@ void hfp_h2_framing_add_header(hfp_h2_framing_t * hfp_h2_framing, uint8_t * buff
 void hfp_codec_init_msbc(hfp_codec_t * hfp_codec, btstack_sbc_encoder_state_t * msbc_encoder_context){
     memset(hfp_codec, 0, sizeof(hfp_codec_t));
     hfp_h2_framing_init(&hfp_codec->h2_framing);
+    hfp_codec->write_pos = 0;
     hfp_codec->samples_per_frame = 120;
     hfp_codec->encode = &hfp_codec_encode_msbc;
     hfp_codec->msbc_encoder_context = msbc_encoder_context;
@@ -101,6 +102,7 @@ void hfp_codec_init_msbc(hfp_codec_t * hfp_codec, btstack_sbc_encoder_state_t *
 void hfp_codec_init_lc3_swb(hfp_codec_t * hfp_codec, const btstack_lc3_encoder_t * lc3_encoder, void * lc3_encoder_context){
     memset(hfp_codec, 0, sizeof(hfp_codec_t));
     hfp_h2_framing_init(&hfp_codec->h2_framing);
+    hfp_codec->write_pos = 0;
     hfp_codec->samples_per_frame = 240;
     hfp_codec->encode = &hfp_codec_encode_lc3swb;
     // init lc3 encoder