diff --git a/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_ble.c b/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_ble.c
index 43a26e7..0444ef8 100644
--- a/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_ble.c
+++ b/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_ble.c
@@ -115,7 +115,6 @@ static ble_gap_id_key_t    const * m_gap_ids[1];
 
 // Adafruit
 static uint8_t _adv_handle = BLE_GAP_ADV_SET_HANDLE_NOT_SET;
-extern void blinky_fast_set(bool isFast);
 
 /**@brief     Function updating Service Changed CCCD and indicate a service change to peer.
  *
@@ -590,7 +589,7 @@ static void on_dfu_evt(ble_dfu_t * p_dfu, ble_dfu_evt_t * p_evt)
             break;
 
         case BLE_DFU_PACKET_WRITE:
-            blinky_fast_set(true);
+            led_blink_fast(true);
             on_dfu_pkt_write(p_dfu, p_evt);
             break;
 
@@ -747,7 +746,7 @@ static void on_ble_evt(ble_evt_t * p_ble_evt)
 
                 m_direct_adv_cnt = APP_DIRECTED_ADV_TIMEOUT;
 
-                blinky_fast_set(false);
+                led_blink_fast(false);
 
                 err_code = sd_ble_gatts_sys_attr_get(m_conn_handle, 
                                                      sys_attr,
diff --git a/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_serial.c b/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_serial.c
index db227e6..1d6beee 100644
--- a/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_serial.c
+++ b/lib/sdk11/components/libraries/bootloader_dfu/dfu_transport_serial.c
@@ -19,6 +19,7 @@
 #include "hci_transport.h"
 #include "app_timer.h"
 #include "app_scheduler.h"
+#include "boards/boards.h"
 
 #define MAX_BUFFERS          4u                                                      /**< Maximum number of buffers that can be received queued without being consumed. */
 
@@ -208,7 +209,6 @@ static void process_dfu_packet(void * p_event_data, uint16_t event_size)
                 packet = &m_data_queue.data_packet[index];
                 if (INVALID_PACKET != packet->packet_type)
                 {
-                    extern void blinky_fast_set(bool isFast);
                     switch (DATA_QUEUE_ELEMENT_GET_PTYPE(index))
                     {
                         case DATA_PACKET:
@@ -227,14 +227,14 @@ static void process_dfu_packet(void * p_event_data, uint16_t event_size)
                             retval = dfu_init_pkt_complete();
                             APP_ERROR_CHECK(retval);
 
-                            blinky_fast_set(true);
+                            led_blink_fast(true);
                             break;
 
                         case STOP_DATA_PACKET:
                             (void)dfu_image_validate();
                             (void)dfu_image_activate();
 
-                            blinky_fast_set(false);
+                            led_blink_fast(false);
 
                             // Break the loop by returning.
                             return;
diff --git a/src/boards/boards.h b/src/boards/boards.h
index f25305e..0c6560a 100644
--- a/src/boards/boards.h
+++ b/src/boards/boards.h
@@ -49,6 +49,8 @@ static inline void led_off(uint32_t pin)
   led_control(pin, false);
 }
 
+void led_blink_fast(bool enable);
+
 //--------------------------------------------------------------------+
 // BUTTONS
 //--------------------------------------------------------------------+
diff --git a/src/main.c b/src/main.c
index 69ac105..ab0c897 100644
--- a/src/main.c
+++ b/src/main.c
@@ -174,9 +174,9 @@ void SysTick_Handler(void)
   blinky_handler();
 }
 
-void blinky_fast_set(bool isFast)
+void led_blink_fast(bool enable)
 {
-  _fast_blink = isFast;
+  _fast_blink = enable;
 }
 
 void board_init(void)
@@ -417,7 +417,7 @@ void freset_erase_and_wait(pstorage_handle_t* hdl, uint32_t addr, uint32_t size)
 void adafruit_factory_reset(void)
 {
   // Blink fast RED and turn on BLUE when erasing
-  blinky_fast_set(true);
+  led_blink_fast(true);
   led_on(LED_BLUE);
 
   static pstorage_handle_t freset_handle = { .block_id = APPDATA_ADDR_START } ;
@@ -432,7 +432,7 @@ void adafruit_factory_reset(void)
   freset_erase_and_wait(&freset_handle, DFU_BANK_0_REGION_START, CODE_PAGE_SIZE);
 
   // back to normal
-  blinky_fast_set(false);
+  led_blink_fast(false);
   led_off(LED_BLUE);
 }
 
diff --git a/src/usb/uf2/ghostfat.c b/src/usb/uf2/ghostfat.c
index a468ab4..3256b09 100644
--- a/src/usb/uf2/ghostfat.c
+++ b/src/usb/uf2/ghostfat.c
@@ -2,6 +2,8 @@
 #include "uf2.h"
 #include "nrf_nvmc.h"
 #include <string.h>
+
+#include "boards/boards.h"
 #include "tusb.h"
 
 #include "bootloader_settings.h"
@@ -130,11 +132,6 @@ static WriteState* state = &_wr_state;
 volatile bool _is_flashing = false;
 static pstorage_handle_t _fat_psh = { .module_id = 0, .block_id = USER_FLASH_END } ;
 
-
-// from main.c to signal writing uf2 is on the way
-extern void blinky_fast_set(bool isFast);
-
-
 static uint32_t get_flash_size(void)
 {
   static uint32_t flash_sz = 0;
@@ -258,7 +255,7 @@ void read_block(uint32_t block_no, uint8_t *data) {
 /** inform bootloader to update setting and reset */
 static void uf2_write_complete(void)
 {
-  blinky_fast_set(false);
+  led_blink_fast(false);
 
   dfu_update_status_t update_status;
 
@@ -307,7 +304,7 @@ void flushFlash() {
         pstorage_module_param_t  fat_psp = { .cb = fat_pstorage_cb};
         pstorage_register(&fat_psp, &_fat_psh);
 
-        blinky_fast_set(true);
+        led_blink_fast(true);
     }
 
     NRF_LOG_DEBUG("Flush at %x", flashAddr);