diff --git a/src/flash_nrf5x.c b/src/flash_nrf5x.c
index bc13aa2..9145a31 100644
--- a/src/flash_nrf5x.c
+++ b/src/flash_nrf5x.c
@@ -53,8 +53,9 @@ void flash_nrf5x_flush (bool need_erase)
   {
     // - nRF52832 dfu via uart can miss incoming byte when erasing because cpu is blocked for > 2ms.
     // Since dfu_prepare_func_app_erase() already erase the page for us, we can skip it here.
-    // - nRF52840 dfu serial/uf2 are USB-based which are DMA and should have no problems. Note MSC uf2
-    // does not erase page in advance like dfu serial
+    // - nRF52840 dfu serial/uf2 are USB-based which are DMA and should have no problems.
+    //
+    // Note: MSC uf2 does not erase page in advance like dfu serial
     if ( need_erase ) nrf_nvmc_page_erase(_fl_addr);
 
     nrf_nvmc_write_words(_fl_addr, (uint32_t *) _fl_buf, FLASH_PAGE_SIZE / 4);
diff --git a/src/usb/msc_uf2.c b/src/usb/msc_uf2.c
index a241055..4f9109a 100644
--- a/src/usb/msc_uf2.c
+++ b/src/usb/msc_uf2.c
@@ -39,6 +39,8 @@
 
 #if CFG_TUD_MSC
 
+#include "bootloader.h"
+
 /*------------------------------------------------------------------*/
 /* MACRO TYPEDEF CONSTANT ENUM
  *------------------------------------------------------------------*/
@@ -46,8 +48,10 @@
 /*------------------------------------------------------------------*/
 /* UF2
  *------------------------------------------------------------------*/
+static WriteState _wr_state = { 0 };
+
 void read_block(uint32_t block_no, uint8_t *data);
-int write_block(uint32_t block_no, uint8_t *data, bool quiet/*, WriteState *state*/);
+int write_block(uint32_t block_no, uint8_t *data, bool quiet, WriteState *state);
 
 //--------------------------------------------------------------------+
 // tinyusb callbacks
@@ -137,7 +141,7 @@ int32_t tud_msc_write10_cb (uint8_t lun, uint32_t lba, uint32_t offset, uint8_t*
   uint32_t count = 0;
   int wr_ret;
 
-  while ( (count < bufsize) && ((wr_ret = write_block(lba, buffer, false)) > 0) )
+  while ( (count < bufsize) && ((wr_ret = write_block(lba, buffer, false, &_wr_state)) > 0) )
   {
     lba++;
     buffer += 512;
@@ -148,6 +152,25 @@ int32_t tud_msc_write10_cb (uint8_t lun, uint32_t lba, uint32_t offset, uint8_t*
   return  (wr_ret < 0) ? bufsize : count;
 }
 
+// Callback invoked when WRITE10 command is completed (status received and accepted by host).
+void tud_msc_write10_complete_cb(uint8_t lun)
+{
+  // uf2 file writing is complete --> complete DFU process
+  if ( _wr_state.numBlocks && (_wr_state.numWritten >= _wr_state.numBlocks) )
+  {
+    led_state(STATE_WRITING_FINISHED);
+
+    dfu_update_status_t update_status;
+
+    memset(&update_status, 0, sizeof(dfu_update_status_t ));
+    update_status.status_code = DFU_UPDATE_APP_COMPLETE;
+    update_status.app_crc     = 0; // skip CRC checking with uf2 upgrade
+    update_status.app_size    = _wr_state.numBlocks*256;
+
+    bootloader_dfu_update_process(update_status);
+  }
+}
+
 void tud_msc_capacity_cb(uint8_t lun, uint32_t* block_count, uint16_t* block_size)
 {
   (void) lun;
diff --git a/src/usb/uf2/ghostfat.c b/src/usb/uf2/ghostfat.c
index f4311cf..1f41c10 100644
--- a/src/usb/uf2/ghostfat.c
+++ b/src/usb/uf2/ghostfat.c
@@ -119,8 +119,6 @@ static FAT_BootBlock const BootBlock = {
 #define NRF_LOG_DEBUG(...)
 #define NRF_LOG_WARNING(...)
 
-static WriteState _wr_state = { 0 };
-
 // get current.uf2 flash size in bytes, round up to 256 bytes
 static uint32_t current_flash_size(void)
 {
@@ -241,21 +239,6 @@ void read_block(uint32_t block_no, uint8_t *data) {
 /* Write UF2
  *------------------------------------------------------------------*/
 
-/** uf2 upgrade complete -> inform bootloader to update setting and reset */
-static void uf2_write_complete(uint32_t numBlocks)
-{
-  led_state(STATE_WRITING_FINISHED);
-
-  dfu_update_status_t update_status;
-
-  memset(&update_status, 0, sizeof(dfu_update_status_t ));
-  update_status.status_code = DFU_UPDATE_APP_COMPLETE;
-  update_status.app_crc     = 0; // skip CRC checking with uf2 upgrade
-  update_status.app_size    = numBlocks*256;
-
-  bootloader_dfu_update_process(update_status);
-}
-
 /** Write an block
  *
  * @return number of bytes processed, only 3 following values
@@ -263,9 +246,8 @@ static void uf2_write_complete(uint32_t numBlocks)
  * 512 : write is successful
  *   0 : is busy with flashing, tinyusb stack will call write_block again with the same parameters later on
  */
-int write_block(uint32_t block_no, uint8_t *data, bool quiet/*, WriteState *state*/) {
+int write_block(uint32_t block_no, uint8_t *data, bool quiet, WriteState *state) {
     UF2_Block *bl = (void *)data;
-    WriteState* state = &_wr_state;
 
      NRF_LOG_DEBUG("Write magic: %x", bl->magicStart0);
 
@@ -318,8 +300,6 @@ int write_block(uint32_t block_no, uint8_t *data, bool quiet/*, WriteState *stat
             if (state->numWritten >= state->numBlocks) {
                 // flush last blocks
                 flash_nrf5x_flush(true);
-
-                uf2_write_complete(state->numBlocks);
             }
         }
         NRF_LOG_DEBUG("wr %d=%d (of %d)", state->numWritten, bl->blockNo, bl->numBlocks);