diff --git a/applications/bt/bt_service/bt.c b/applications/bt/bt_service/bt.c
index 074ab980..97cc156b 100755
--- a/applications/bt/bt_service/bt.c
+++ b/applications/bt/bt_service/bt.c
@@ -132,9 +132,9 @@ static void bt_rpc_send_bytes_callback(void* context, uint8_t* bytes, size_t byt
     size_t bytes_sent = 0;
     while(bytes_sent < bytes_len) {
         size_t bytes_remain = bytes_len - bytes_sent;
-        if(bytes_remain > FURI_HAL_BT_SERIAL_PACKET_SIZE_MAX) {
-            furi_hal_bt_serial_tx(&bytes[bytes_sent], FURI_HAL_BT_SERIAL_PACKET_SIZE_MAX);
-            bytes_sent += FURI_HAL_BT_SERIAL_PACKET_SIZE_MAX;
+        if(bytes_remain > bt->max_packet_size) {
+            furi_hal_bt_serial_tx(&bytes[bytes_sent], bt->max_packet_size);
+            bytes_sent += bt->max_packet_size;
         } else {
             furi_hal_bt_serial_tx(&bytes[bytes_sent], bytes_remain);
             bytes_sent += bytes_remain;
diff --git a/firmware/targets/f6/ble-glue/app_conf.h b/firmware/targets/f6/ble-glue/app_conf.h
index eebdbbdb..059e8e4f 100644
--- a/firmware/targets/f6/ble-glue/app_conf.h
+++ b/firmware/targets/f6/ble-glue/app_conf.h
@@ -139,7 +139,7 @@
 /**
  * Maximum supported ATT_MTU size
  */
-#define CFG_BLE_MAX_ATT_MTU             (251)
+#define CFG_BLE_MAX_ATT_MTU             (489)
 
 /**
  * Size of the storage area for Attribute values
diff --git a/firmware/targets/f6/ble-glue/serial_service.c b/firmware/targets/f6/ble-glue/serial_service.c
index 4c70ccb0..ab201546 100644
--- a/firmware/targets/f6/ble-glue/serial_service.c
+++ b/firmware/targets/f6/ble-glue/serial_service.c
@@ -184,17 +184,31 @@ bool serial_svc_is_started() {
     return serial_svc != NULL;
 }
 
-bool serial_svc_update_tx(uint8_t* data, uint8_t data_len) {
+bool serial_svc_update_tx(uint8_t* data, uint16_t data_len) {
     if(data_len > SERIAL_SVC_DATA_LEN_MAX) {
         return false;
     }
-    tBleStatus result = aci_gatt_update_char_value(serial_svc->svc_handle,
-                                        serial_svc->tx_char_handle,
+
+    for(uint16_t remained = data_len; remained > 0;) {
+        uint8_t value_len = MIN(SERIAL_SVC_CHAR_VALUE_LEN_MAX, remained);
+        uint16_t value_offset = data_len - remained;
+        remained -= value_len;
+
+        tBleStatus result  = aci_gatt_update_char_value_ext(
                                         0,
+                                        serial_svc->svc_handle,
+                                        serial_svc->tx_char_handle,
+                                        remained ? 0x00 : 0x02,
                                         data_len,
-                                        data);
-    if(result) {
-        FURI_LOG_E(TAG, "Failed updating TX characteristic: %d", result);
+                                        value_offset,
+                                        value_len,
+                                        data + value_offset);
+
+        if(result) {
+            FURI_LOG_E(TAG, "Failed updating TX characteristic: %d", result);
+            return false;
+        }
     }
-    return result != BLE_STATUS_SUCCESS;
+
+    return true;
 }
diff --git a/firmware/targets/f6/ble-glue/serial_service.h b/firmware/targets/f6/ble-glue/serial_service.h
index 3ea548af..1c365c0e 100644
--- a/firmware/targets/f6/ble-glue/serial_service.h
+++ b/firmware/targets/f6/ble-glue/serial_service.h
@@ -3,7 +3,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-#define SERIAL_SVC_DATA_LEN_MAX (248)
+#define SERIAL_SVC_DATA_LEN_MAX (486)
 
 #ifdef __cplusplus
 extern "C" {
@@ -36,7 +36,7 @@ void serial_svc_stop();
 
 bool serial_svc_is_started();
 
-bool serial_svc_update_tx(uint8_t* data, uint8_t data_len);
+bool serial_svc_update_tx(uint8_t* data, uint16_t data_len);
 
 #ifdef __cplusplus
 }
diff --git a/firmware/targets/f7/ble-glue/app_conf.h b/firmware/targets/f7/ble-glue/app_conf.h
index eebdbbdb..059e8e4f 100644
--- a/firmware/targets/f7/ble-glue/app_conf.h
+++ b/firmware/targets/f7/ble-glue/app_conf.h
@@ -139,7 +139,7 @@
 /**
  * Maximum supported ATT_MTU size
  */
-#define CFG_BLE_MAX_ATT_MTU             (251)
+#define CFG_BLE_MAX_ATT_MTU             (489)
 
 /**
  * Size of the storage area for Attribute values
diff --git a/firmware/targets/f7/ble-glue/serial_service.c b/firmware/targets/f7/ble-glue/serial_service.c
index 4c70ccb0..ab201546 100644
--- a/firmware/targets/f7/ble-glue/serial_service.c
+++ b/firmware/targets/f7/ble-glue/serial_service.c
@@ -184,17 +184,31 @@ bool serial_svc_is_started() {
     return serial_svc != NULL;
 }
 
-bool serial_svc_update_tx(uint8_t* data, uint8_t data_len) {
+bool serial_svc_update_tx(uint8_t* data, uint16_t data_len) {
     if(data_len > SERIAL_SVC_DATA_LEN_MAX) {
         return false;
     }
-    tBleStatus result = aci_gatt_update_char_value(serial_svc->svc_handle,
-                                        serial_svc->tx_char_handle,
+
+    for(uint16_t remained = data_len; remained > 0;) {
+        uint8_t value_len = MIN(SERIAL_SVC_CHAR_VALUE_LEN_MAX, remained);
+        uint16_t value_offset = data_len - remained;
+        remained -= value_len;
+
+        tBleStatus result  = aci_gatt_update_char_value_ext(
                                         0,
+                                        serial_svc->svc_handle,
+                                        serial_svc->tx_char_handle,
+                                        remained ? 0x00 : 0x02,
                                         data_len,
-                                        data);
-    if(result) {
-        FURI_LOG_E(TAG, "Failed updating TX characteristic: %d", result);
+                                        value_offset,
+                                        value_len,
+                                        data + value_offset);
+
+        if(result) {
+            FURI_LOG_E(TAG, "Failed updating TX characteristic: %d", result);
+            return false;
+        }
     }
-    return result != BLE_STATUS_SUCCESS;
+
+    return true;
 }
diff --git a/firmware/targets/f7/ble-glue/serial_service.h b/firmware/targets/f7/ble-glue/serial_service.h
index 3ea548af..6e19f86d 100644
--- a/firmware/targets/f7/ble-glue/serial_service.h
+++ b/firmware/targets/f7/ble-glue/serial_service.h
@@ -3,7 +3,8 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-#define SERIAL_SVC_DATA_LEN_MAX (248)
+#define SERIAL_SVC_DATA_LEN_MAX (486)
+#define SERIAL_SVC_CHAR_VALUE_LEN_MAX (243)
 
 #ifdef __cplusplus
 extern "C" {
@@ -36,7 +37,7 @@ void serial_svc_stop();
 
 bool serial_svc_is_started();
 
-bool serial_svc_update_tx(uint8_t* data, uint8_t data_len);
+bool serial_svc_update_tx(uint8_t* data, uint16_t data_len);
 
 #ifdef __cplusplus
 }