diff --git a/components/bt/bt.c b/components/bt/bt.c
index 6890bcf12..c53e9c933 100644
--- a/components/bt/bt.c
+++ b/components/bt/bt.c
@@ -398,10 +398,8 @@ esp_err_t esp_bt_controller_mem_release(esp_bt_mode_t mode)
     bool update = true;
     intptr_t mem_start, mem_end;
 
-    //get the mode which can be released, skip the mode which is running
-    mode &= ~btdm_controller_get_mode();
-    if (mode == 0x0) {
-        return ESP_ERR_INVALID_ARG;
+    if (btdm_controller_status != ESP_BT_CONTROLLER_STATUS_IDLE) {
+        return ESP_ERR_INVALID_STATE;
     }
 
     //already relesed
diff --git a/components/bt/include/esp_bt.h b/components/bt/include/esp_bt.h
index 30a535015..dcd531b6d 100644
--- a/components/bt/include/esp_bt.h
+++ b/components/bt/include/esp_bt.h
@@ -212,20 +212,18 @@ void esp_vhci_host_register_callback(const esp_vhci_host_callback_t *callback);
  * it can release the .bbs, .data and other section to heap.
  * The total size is about 70k bytes.
  *
- * If esp_bt_controller_enable(mode) has already been called, calling
- * esp_bt_controller_mem_release(ESP_BT_MODE_BTDM) will automatically
- * release all memory which is not needed for the currently enabled
- * Bluetooth controller mode.
+ * esp_bt_controller_mem_release(mode) should be called only before esp_bt_controller_init()
+ * or after esp_bt_controller_deinit().
  *
- * For example, calling esp_bt_controller_enable(ESP_BT_MODE_BLE) then
- * esp_bt_controller_mem_release(ESP_BT_MODE_BTDM) will enable BLE modes
- * and release memory only used by BT Classic. Also, call esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT)
- * is the same.
+ * Note that once BT controller memory is released, the process cannot be reversed. It means you can not use the bluetooth
+ * mode which you have released by this function.
  *
- * Note that once BT controller memory is released, the process cannot be reversed.
  * If your firmware will later upgrade the Bluetooth controller mode (BLE -> BT Classic or disabled -> enabled)
  * then do not call this function.
  *
+ * If the app calls esp_bt_controller_enable(ESP_BT_MODE_BLE) to use BLE only then it is safe to call
+ * esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT) at initialisation time to free unused BT Classic memory.
+ *
  * If user never use bluetooth controller, could call esp_bt_controller_mem_release(ESP_BT_MODE_BTDM)
  * before esp_bt_controller_init or after esp_bt_controller_deinit.
  *
diff --git a/examples/bluetooth/a2dp_sink/main/main.c b/examples/bluetooth/a2dp_sink/main/main.c
index e77aa449c..aa489f583 100644
--- a/examples/bluetooth/a2dp_sink/main/main.c
+++ b/examples/bluetooth/a2dp_sink/main/main.c
@@ -83,6 +83,7 @@ void app_main()
 #endif
 
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_BLE));
 
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     if (esp_bt_controller_init(&bt_cfg) != ESP_OK) {
diff --git a/examples/bluetooth/ble_eddystone/main/esp_eddystone_demo.c b/examples/bluetooth/ble_eddystone/main/esp_eddystone_demo.c
index 7def481ae..95f239431 100644
--- a/examples/bluetooth/ble_eddystone/main/esp_eddystone_demo.c
+++ b/examples/bluetooth/ble_eddystone/main/esp_eddystone_demo.c
@@ -166,9 +166,10 @@ void esp_eddystone_init(void)
 void app_main()
 {
     ESP_ERROR_CHECK(nvs_flash_init());
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     esp_bt_controller_init(&bt_cfg);
-    esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    esp_bt_controller_enable(ESP_BT_MODE_BLE);
  
     esp_eddystone_init();
 
diff --git a/examples/bluetooth/ble_ibeacon/main/ibeacon_demo.c b/examples/bluetooth/ble_ibeacon/main/ibeacon_demo.c
index e0d71ba8e..ded437828 100644
--- a/examples/bluetooth/ble_ibeacon/main/ibeacon_demo.c
+++ b/examples/bluetooth/ble_ibeacon/main/ibeacon_demo.c
@@ -160,9 +160,10 @@ void ble_ibeacon_init(void)
 void app_main()
 {
     ESP_ERROR_CHECK(nvs_flash_init());
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     esp_bt_controller_init(&bt_cfg);
-    esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    esp_bt_controller_enable(ESP_BT_MODE_BLE);
 
     ble_ibeacon_init();
 
diff --git a/examples/bluetooth/ble_spp_client/main/spp_client_demo.c b/examples/bluetooth/ble_spp_client/main/spp_client_demo.c
index b2968b38c..855cc0f76 100644
--- a/examples/bluetooth/ble_spp_client/main/spp_client_demo.c
+++ b/examples/bluetooth/ble_spp_client/main/spp_client_demo.c
@@ -956,6 +956,9 @@ static void spp_uart_init(void)
 void app_main()
 {
     esp_err_t ret;
+
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
 
     nvs_flash_init();
@@ -965,7 +968,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTC_TAG, "%s enable controller failed\n", __func__);
         return;
diff --git a/examples/bluetooth/ble_spp_server/main/ble_spp_server_demo.c b/examples/bluetooth/ble_spp_server/main/ble_spp_server_demo.c
index 399dc7e1d..6ed2a2380 100644
--- a/examples/bluetooth/ble_spp_server/main/ble_spp_server_demo.c
+++ b/examples/bluetooth/ble_spp_server/main/ble_spp_server_demo.c
@@ -658,14 +658,23 @@ void app_main()
     esp_err_t ret;
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
 
-    nvs_flash_init();
+    // Initialize NVS
+    ret = nvs_flash_init();
+    if (ret == ESP_ERR_NVS_NO_FREE_PAGES) {
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        ret = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK( ret );
+
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
         ESP_LOGE(GATTS_TABLE_TAG, "%s enable controller failed\n", __func__);
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTS_TABLE_TAG, "%s enable controller failed\n", __func__);
         return;
diff --git a/examples/bluetooth/blufi/main/blufi_example_main.c b/examples/bluetooth/blufi/main/blufi_example_main.c
index 5895d5e28..a780d606c 100644
--- a/examples/bluetooth/blufi/main/blufi_example_main.c
+++ b/examples/bluetooth/blufi/main/blufi_example_main.c
@@ -331,13 +331,15 @@ void app_main()
 
     initialise_wifi();
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
         BLUFI_ERROR("%s initialize bt controller failed\n", __func__);
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         BLUFI_ERROR("%s enable bt controller failed\n", __func__);
         return;
diff --git a/examples/bluetooth/gatt_client/main/gattc_demo.c b/examples/bluetooth/gatt_client/main/gattc_demo.c
index d9bb810f9..3dac18266 100644
--- a/examples/bluetooth/gatt_client/main/gattc_demo.c
+++ b/examples/bluetooth/gatt_client/main/gattc_demo.c
@@ -425,6 +425,8 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
@@ -432,7 +434,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTC_TAG, "%s enable controller failed, error code = %x\n", __func__, ret);
         return;
diff --git a/examples/bluetooth/gatt_security_client/main/example_ble_sec_gattc_demo.c b/examples/bluetooth/gatt_security_client/main/example_ble_sec_gattc_demo.c
index a71d496df..3679b33af 100644
--- a/examples/bluetooth/gatt_security_client/main/example_ble_sec_gattc_demo.c
+++ b/examples/bluetooth/gatt_security_client/main/example_ble_sec_gattc_demo.c
@@ -468,6 +468,8 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
@@ -475,7 +477,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTC_TAG, "%s enable controller failed, error code = %x\n", __func__, ret);
         return;
diff --git a/examples/bluetooth/gatt_security_server/main/example_ble_sec_gatts_demo.c b/examples/bluetooth/gatt_security_server/main/example_ble_sec_gatts_demo.c
index eb328c4f6..5b7d460c4 100644
--- a/examples/bluetooth/gatt_security_server/main/example_ble_sec_gatts_demo.c
+++ b/examples/bluetooth/gatt_security_server/main/example_ble_sec_gatts_demo.c
@@ -476,13 +476,15 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
         ESP_LOGE(GATTS_TABLE_TAG, "%s init controller failed", __func__);
         return;
     }
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTS_TABLE_TAG, "%s enable controller failed", __func__);
         return;
diff --git a/examples/bluetooth/gatt_server/main/gatts_demo.c b/examples/bluetooth/gatt_server/main/gatts_demo.c
index 1bc35e4fd..4e298dcae 100644
--- a/examples/bluetooth/gatt_server/main/gatts_demo.c
+++ b/examples/bluetooth/gatt_server/main/gatts_demo.c
@@ -691,6 +691,8 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
@@ -698,7 +700,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTS_TAG, "%s enable controller failed\n", __func__);
         return;
diff --git a/examples/bluetooth/gatt_server_service_table/main/gatts_table_creat_demo.c b/examples/bluetooth/gatt_server_service_table/main/gatts_table_creat_demo.c
index 25aee6964..a38babd65 100644
--- a/examples/bluetooth/gatt_server_service_table/main/gatts_table_creat_demo.c
+++ b/examples/bluetooth/gatt_server_service_table/main/gatts_table_creat_demo.c
@@ -522,6 +522,8 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
@@ -529,7 +531,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTS_TABLE_TAG, "%s enable controller failed\n", __func__);
         return;
diff --git a/examples/bluetooth/gattc_multi_connect/main/gattc_multi_connect.c b/examples/bluetooth/gattc_multi_connect/main/gattc_multi_connect.c
index 6e19d57b1..eb09cee23 100644
--- a/examples/bluetooth/gattc_multi_connect/main/gattc_multi_connect.c
+++ b/examples/bluetooth/gattc_multi_connect/main/gattc_multi_connect.c
@@ -896,6 +896,8 @@ void app_main()
     }
     ESP_ERROR_CHECK( ret );
 
+    ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
+
     esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
     ret = esp_bt_controller_init(&bt_cfg);
     if (ret) {
@@ -903,7 +905,7 @@ void app_main()
         return;
     }
 
-    ret = esp_bt_controller_enable(ESP_BT_MODE_BTDM);
+    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
     if (ret) {
         ESP_LOGE(GATTC_TAG, "%s enable controller failed\n", __func__);
         return;