diff --git a/src/l2cap.c b/src/l2cap.c
index 53878c413..009ebdb85 100644
--- a/src/l2cap.c
+++ b/src/l2cap.c
@@ -911,10 +911,10 @@ static void l2cap_run(void){
 #ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE
         // send s-frame to acknowledge received packets
         if (!hci_can_send_acl_packet_now(channel->con_handle)) continue;
-        if (channel->req_seq != 0xff){
-            log_info("try to send s-frame");
+        if (channel->send_supervisor_frame_receiver_ready){
+            channel->send_supervisor_frame_receiver_ready = 0;;
+            log_info("Send S-Frame: RR %u", channel->req_seq);
             uint16_t control = l2cap_encanced_control_field_for_supevisor_frame( L2CAP_SUPERVISORY_FUNCTION_RR_RECEIVER_READY, 0, 0, channel->req_seq);
-            channel->req_seq = 0xff;
             l2cap_ertm_send_supervisor_frame(channel, control);
         }
 #endif
@@ -1130,10 +1130,6 @@ static l2cap_channel_t * l2cap_create_channel_entry(btstack_packet_handler_t pac
     channel->remote_sig_id = L2CAP_SIG_ID_INVALID;
     channel->local_sig_id = L2CAP_SIG_ID_INVALID;
 
-#ifdef ENABLE_L2CAP_ENHANCED_RETRANSMISSION_MODE
-    channel->req_seq = 0xff;
-#endif
-
     return channel;
 }
 #endif
@@ -2442,6 +2438,7 @@ static void l2cap_acl_handler(uint8_t packet_type, uint16_t channel, uint8_t *pa
                         if (l2cap_channel->expected_tx_seq == tx_seq){
                             log_info("Received expected frame with TxSeq == ExpectedTxSeq == %02u", tx_seq);
                             l2cap_channel->req_seq = tx_seq;
+                            l2cap_channel->send_supervisor_frame_receiver_ready = 1;
                             l2cap_channel->expected_tx_seq = l2cap_next_ertm_seq_nr(l2cap_channel->expected_tx_seq);
                             uint16_t sdu_length;
                             uint16_t segment_length;
diff --git a/src/l2cap.h b/src/l2cap.h
index 1f967196a..3c034b800 100644
--- a/src/l2cap.h
+++ b/src/l2cap.h
@@ -207,16 +207,19 @@ typedef struct {
     uint8_t local_max_transmit;
     uint8_t remote_max_transmit;
     
-    // if ertm is not mandatory, allow fallback to L2CAP Basic Mode
+    // if ertm is not mandatory, allow fallback to L2CAP Basic Mode - flag
     uint8_t ertm_mandatory;
 
+    // receiver: send RR frame - flag
+    uint8_t send_supervisor_frame_receiver_ready;
+
     // sender: next seq nr used for sending
     uint8_t next_tx_seq;
 
     // receiver: value of tx_seq in next expected i-frame
     uint8_t expected_tx_seq;
 
-    // receiver: request transmiissoin with tx_seq = req_seq and ack up to and including req_seq - 1, 0xff if no ack to send
+    // receiver: request transmiissoin with tx_seq = req_seq and ack up to and including req_seq
     uint8_t req_seq;
 
     // max um out-of-order packets // tx_window