diff --git a/src/hsp_hs.c b/src/hsp_hs.c
index b24395636..ab4319478 100644
--- a/src/hsp_hs.c
+++ b/src/hsp_hs.c
@@ -137,7 +137,7 @@ static void emit_event(uint8_t event_subtype, uint8_t value){
 // remote audio volume control
 // AG +VGM=13 [0..15] ; HS AT+VGM=6 | AG OK
 
-static int hsp_hs_send_str_over_rfcomm(uint16_t cid, char * command){
+static int hsp_hs_send_str_over_rfcomm(uint16_t cid, const char * command){
     if (!rfcomm_can_send_packet_now(rfcomm_cid)) return 1;
     int err = rfcomm_send_internal(cid, (uint8_t*) command, strlen(command));
     if (err){