diff --git a/port/stm32-f4discovery-usb/Core/Src/main.c b/port/stm32-f4discovery-usb/Core/Src/main.c
index 3ff4f9f34..7451d114d 100644
--- a/port/stm32-f4discovery-usb/Core/Src/main.c
+++ b/port/stm32-f4discovery-usb/Core/Src/main.c
@@ -23,6 +23,7 @@
 
 /* Private includes ----------------------------------------------------------*/
 /* USER CODE BEGIN Includes */
+#include "port.h"
 
 /* USER CODE END Includes */
 
@@ -90,8 +91,7 @@ int main(void)
   MX_GPIO_Init();
   MX_USB_HOST_Init();
   /* USER CODE BEGIN 2 */
-  printf("Hello RTT\n");
-
+  port_main();
   /* USER CODE END 2 */
 
   /* Infinite loop */
diff --git a/port/stm32-f4discovery-usb/port/hci_transport_h2_stm32.c b/port/stm32-f4discovery-usb/port/hci_transport_h2_stm32.c
index 47c2783df..c835b78ad 100644
--- a/port/stm32-f4discovery-usb/port/hci_transport_h2_stm32.c
+++ b/port/stm32-f4discovery-usb/port/hci_transport_h2_stm32.c
@@ -43,12 +43,30 @@
  *  HCI Transport API implementation for STM32Cube USB Host Stack
  */
 
-#include "hci_transport_h2_stm32.h"
+// include STM32 first to avoid warning about redefinition of UNUSED
+#include "usb_host.h"
+
 #include <stddef.h>
+
+#include "hci_transport_h2_stm32.h"
+
 #include "btstack_debug.h"
+#include "btstack_run_loop.h"
 
 static  void (*packet_handler)(uint8_t packet_type, uint8_t *packet, uint16_t size) = NULL;
 
+// data source for integration with BTstack Runloop
+static btstack_data_source_t transport_data_source;
+
+static void hci_transport_h2_stm32_process(btstack_data_source_t *ds, btstack_data_source_callback_type_t callback_type) {
+    switch (callback_type){
+        case DATA_SOURCE_CALLBACK_POLL:
+            MX_USB_HOST_Process();
+            break;
+        default:
+            break;
+    }
+}
 
 static void hci_transport_h2_stm32_init(const void * transport_config){
     UNUSED(transport_config);
@@ -56,12 +74,17 @@ static void hci_transport_h2_stm32_init(const void * transport_config){
 }
 
 static int hci_transport_h2_stm32_open(void){
-    log_info("hci_transport_h2_stm32_open");
+    // set up polling data_source
+    btstack_run_loop_set_data_source_handler(&transport_data_source, &hci_transport_h2_stm32_process);
+    btstack_run_loop_enable_data_source_callbacks(&transport_data_source, DATA_SOURCE_CALLBACK_POLL);
+    btstack_run_loop_add_data_source(&transport_data_source);
     return 0;
 }
 
 static int hci_transport_h2_stm32_close(void){
-    log_info("hci_transport_h2_stm32_close");
+    // remove data source
+    btstack_run_loop_disable_data_source_callbacks(&transport_data_source, DATA_SOURCE_CALLBACK_POLL);
+    btstack_run_loop_remove_data_source(&transport_data_source);
     return -1;
 }
 
@@ -70,7 +93,6 @@ static void hci_transport_h2_stm32_register_packet_handler(void (*handler)(uint8
 }
 
 static int hci_transport_h2_stm32_can_send_now(uint8_t packet_type){
-    log_info("hci_transport_h2_stm32_can_send_now");
     return 0;
 }