diff --git a/examples/device/cdc_msc_hid/src/main.c b/examples/device/cdc_msc_hid/src/main.c
index 53161fe83..1fa0fead1 100644
--- a/examples/device/cdc_msc_hid/src/main.c
+++ b/examples/device/cdc_msc_hid/src/main.c
@@ -38,7 +38,7 @@
 /* Blink pattern
  * - 250 ms  : device not mounted
  * - 1000 ms : device mounted
- * - 2000 ms : device is suspended
+ * - 2500 ms : device is suspended
  */
 static uint32_t blink_interval_ms = 250;
 
@@ -210,6 +210,18 @@ void tud_umount_cb(void)
   blink_interval_ms = 250;
 }
 
+// Invoked when device is suspended
+void tud_suspend_cb(bool remote_wakeup_en)
+{
+  (void) remote_wakeup_en;
+  blink_interval_ms = 2500;
+}
+
+void tud_resume_cb(void)
+{
+  blink_interval_ms = 1000;
+}
+
 //--------------------------------------------------------------------+
 // BLINKING TASK
 //--------------------------------------------------------------------+
diff --git a/src/device/dcd.h b/src/device/dcd.h
index f47c3714a..8dafef66d 100644
--- a/src/device/dcd.h
+++ b/src/device/dcd.h
@@ -48,7 +48,7 @@ typedef enum
   DCD_EVENT_SETUP_RECEIVED,
   DCD_EVENT_XFER_COMPLETE,
 
-  USBD_EVT_FUNC_CALL
+  USBD_EVENT_FUNC_CALL
 } dcd_eventid_t;
 
 typedef struct ATTR_ALIGNED(4)
@@ -67,7 +67,7 @@ typedef struct ATTR_ALIGNED(4)
       uint32_t len;
     }xfer_complete;
 
-    // USBD_EVT_FUNC_CALL
+    // USBD_EVENT_FUNC_CALL
     struct {
       void (*func) (void*);
       void* param;
diff --git a/src/device/usbd.c b/src/device/usbd.c
index 7ca81e8d7..4089cf72c 100644
--- a/src/device/usbd.c
+++ b/src/device/usbd.c
@@ -40,14 +40,20 @@
 // Device Data
 //--------------------------------------------------------------------+
 typedef struct {
-  volatile uint8_t config_num; // 0 is non-configured ~ disconnect
-  bool remote_wakeup_en;
+  volatile uint8_t config_num;
 
-  uint8_t itf2drv[16];      // map interface number to driver (0xff is invalid)
-  uint8_t ep2drv[8][2];     // map endpoint to driver ( 0xff is invalid )
+  struct ATTR_PACKED
+  {
+      volatile uint8_t connected : 1;
+      volatile uint8_t suspended : 1;
+      uint8_t remote_wakeup_en   : 1;
+  };
 
 //  uint8_t ep_busy_mask[2];  // bit mask for busy endpoint
   uint8_t ep_stall_mask[2]; // bit mask for stalled endpoint
+
+  uint8_t itf2drv[16];      // map interface number to driver (0xff is invalid)
+  uint8_t ep2drv[8][2];     // map endpoint to driver ( 0xff is invalid )
 }usbd_device_t;
 
 static usbd_device_t _usbd_dev = { 0 };
@@ -246,8 +252,27 @@ void tud_task (void)
 
     if ( !osal_queue_receive(_usbd_q, &event) ) return;
 
+    // Skip event if device is not connected except BUS_RESET & UNPLUGGED & FUNC_CALL
+    if ( !(_usbd_dev.connected || event.event_id == DCD_EVENT_UNPLUGGED ||
+        event.event_id == DCD_EVENT_BUS_RESET || event.event_id == USBD_EVENT_FUNC_CALL) )
+    {
+      return;
+    }
+
     switch ( event.event_id )
     {
+      case DCD_EVENT_BUS_RESET:
+        usbd_reset(event.rhport);
+        _usbd_dev.connected = 1; // connected after bus reset
+      break;
+
+      case DCD_EVENT_UNPLUGGED:
+        usbd_reset(event.rhport);
+
+        // invoke callback
+        if (tud_umount_cb) tud_umount_cb();
+      break;
+
       case DCD_EVENT_SETUP_RECEIVED:
         // Process control request
         if ( !process_control_request(event.rhport, &event.setup_received) )
@@ -278,19 +303,15 @@ void tud_task (void)
       }
       break;
 
-      case DCD_EVENT_BUS_RESET:
-        usbd_reset(event.rhport);
-        // TODO remove since if task is too slow, we could clear the event of the new attached
-        osal_queue_reset(_usbd_q);
+      // NOTE: When unplugging device, the D+/D- state are unstable and can accidentally meet the
+      // SUSPEND condition ( Idle for 3ms ). Most likely when this happen both suspend and resume
+      // are submitted by DCD before the actual UNPLUGGED
+      case DCD_EVENT_SUSPEND:
+        if (tud_suspend_cb) tud_suspend_cb( _usbd_dev.remote_wakeup_en );
       break;
 
-      case DCD_EVENT_UNPLUGGED:
-        usbd_reset(event.rhport);
-        // TODO remove since if task is too slow, we could clear the event of the new attached
-        osal_queue_reset(_usbd_q);
-
-        // invoke callback
-        if (tud_umount_cb) tud_umount_cb();
+      case DCD_EVENT_RESUME:
+        if (tud_resume_cb) tud_resume_cb();
       break;
 
       case DCD_EVENT_SOF:
@@ -303,7 +324,7 @@ void tud_task (void)
         }
       break;
 
-      case USBD_EVT_FUNC_CALL:
+      case USBD_EVENT_FUNC_CALL:
         if ( event.func_call.func ) event.func_call.func(event.func_call.param);
       break;
 
@@ -555,9 +576,8 @@ static void const* get_descriptor(tusb_control_request_t const * p_request, uint
       }else
       {
         // out of range
-        /* The 0xEE index string is a Microsoft USB extension.
-         * It can be used to tell Windows what driver it should use for the device !!!
-         */
+        // The 0xEE index string is a Microsoft USB extension.
+        // It can be used to tell Windows what driver it should use for the device !!!
         return NULL;
       }
     break;
@@ -587,7 +607,8 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
     break;
 
     case DCD_EVENT_UNPLUGGED:
-      _usbd_dev.config_num = 0; // mark disconnected
+      _usbd_dev.connected = 0;
+      _usbd_dev.config_num = 0;
       osal_queue_send(_usbd_q, event, in_isr);
     break;
 
@@ -595,9 +616,23 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
       // nothing to do now
     break;
 
+    // NOTE: When unplugging device, the D+/D- state are unstable and can accidentally meet the
+    // SUSPEND condition ( Idle for 3ms ). Most likely when this happen both suspend and resume
+    // are submitted by DCD before the actual UNPLUGGED
     case DCD_EVENT_SUSPEND:
+      if (_usbd_dev.connected ) // skip event if disconnected
+      {
+        _usbd_dev.suspended = 1;
+        osal_queue_send(_usbd_q, event, in_isr);
+      }
+    break;
+
     case DCD_EVENT_RESUME:
-      osal_queue_send(_usbd_q, event, in_isr);
+      if (_usbd_dev.connected ) // skip event if disconnected
+      {
+        _usbd_dev.suspended = 0;
+        osal_queue_send(_usbd_q, event, in_isr);
+      }
     break;
 
     case DCD_EVENT_SETUP_RECEIVED:
@@ -606,14 +641,14 @@ void dcd_event_handler(dcd_event_t const * event, bool in_isr)
 
     case DCD_EVENT_XFER_COMPLETE:
       // skip zero-length control status complete event, should dcd notifies us.
-      if ( 0 == tu_edpt_number(event->xfer_complete.ep_addr) && event->xfer_complete.len == 0) break;
+      if ( (0 == tu_edpt_number(event->xfer_complete.ep_addr)) && (event->xfer_complete.len == 0) ) break;
 
       osal_queue_send(_usbd_q, event, in_isr);
       TU_ASSERT(event->xfer_complete.result == XFER_RESULT_SUCCESS,);
     break;
 
-    // Not an DCD event, just a convenient way to defer ISR function should we need
-    case USBD_EVT_FUNC_CALL:
+    // Not an DCD event, just a convenient way to defer ISR function should we need to
+    case USBD_EVENT_FUNC_CALL:
       osal_queue_send(_usbd_q, event, in_isr);
     break;
 
@@ -683,7 +718,7 @@ void usbd_defer_func(osal_task_func_t func, void* param, bool in_isr)
   dcd_event_t event =
   {
       .rhport   = 0,
-      .event_id = USBD_EVT_FUNC_CALL,
+      .event_id = USBD_EVENT_FUNC_CALL,
   };
 
   event.func_call.func  = func;
diff --git a/src/osal/osal.h b/src/osal/osal.h
index 7ceb22125..d6c33de3f 100644
--- a/src/osal/osal.h
+++ b/src/osal/osal.h
@@ -61,7 +61,6 @@ typedef void (*osal_task_func_t)( void * );
    *     osal_queue_t osal_queue_create(osal_queue_def_t* qdef)
    *     osal_queue_receive (osal_queue_t const queue_hdl, void *p_data, uint32_t msec, uint32_t *p_error)
    *     bool osal_queue_send(osal_queue_t const queue_hdl, void const * data, bool in_isr)
-   *     osal_queue_reset()
    *
    * Semaphore
    *    osal_semaphore_def_t, osal_semaphore_t
diff --git a/src/osal/osal_freertos.h b/src/osal/osal_freertos.h
index 639501bbf..973a18546 100644
--- a/src/osal/osal_freertos.h
+++ b/src/osal/osal_freertos.h
@@ -125,11 +125,6 @@ static inline bool osal_queue_send(osal_queue_t const queue_hdl, void const * da
   return in_isr ? xQueueSendToBackFromISR(queue_hdl, data, NULL) : xQueueSendToBack(queue_hdl, data, OSAL_TIMEOUT_WAIT_FOREVER);
 }
 
-static inline void osal_queue_reset(osal_queue_t const queue_hdl)
-{
-  xQueueReset(queue_hdl);
-}
-
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/osal/osal_mynewt.h b/src/osal/osal_mynewt.h
index 9fa9f541e..6f3d05325 100644
--- a/src/osal/osal_mynewt.h
+++ b/src/osal/osal_mynewt.h
@@ -161,11 +161,6 @@ static inline bool osal_queue_send(osal_queue_t const qhdl, void const * data, b
   return true;
 }
 
-static inline void osal_queue_reset(osal_queue_t const queue_hdl)
-{
-  // TODO implement later
-}
-
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/osal/osal_none.h b/src/osal/osal_none.h
index 6144f3e5c..d1d365bbe 100644
--- a/src/osal/osal_none.h
+++ b/src/osal/osal_none.h
@@ -190,13 +190,6 @@ static inline bool osal_queue_send(osal_queue_t const qhdl, void const * data, b
   return success;
 }
 
-static inline void osal_queue_reset(osal_queue_t const qhdl)
-{
-  // tusb_hal_int_disable_all();
-  tu_fifo_clear(&qhdl->ff);
-  // tusb_hal_int_enable_all();
-}
-
 #ifdef __cplusplus
  }
 #endif
diff --git a/src/portable/nordic/nrf5x/dcd_nrf5x.c b/src/portable/nordic/nrf5x/dcd_nrf5x.c
index edaef7cca..e7e9ae016 100644
--- a/src/portable/nordic/nrf5x/dcd_nrf5x.c
+++ b/src/portable/nordic/nrf5x/dcd_nrf5x.c
@@ -205,13 +205,14 @@ void dcd_set_config (uint8_t rhport, uint8_t config_num)
 {
   (void) rhport;
   (void) config_num;
-  // Nothing to do
 
-  // Clear current pending 
+  // Enable usbevent for suspend and resume detection
+  // Since the bus signal D+/D- are stable from now on.
+
+  // Clear current pending first
   NRF_USBD->EVENTCAUSE |= NRF_USBD->EVENTCAUSE;
   NRF_USBD->EVENTS_USBEVENT = 0;
 
-  // Enable usb event for suspend and resume
   NRF_USBD->INTENSET = USBD_INTEN_USBEVENT_Msk;
 }
 
@@ -377,19 +378,18 @@ void USBD_IRQHandler(void)
 
   if ( int_status & USBD_INTEN_USBEVENT_Msk )
   {
-    uint32_t const evt_cause = NRF_USBD->EVENTCAUSE;
+    uint32_t const evt_cause = NRF_USBD->EVENTCAUSE & (USBD_EVENTCAUSE_SUSPEND_Msk | USBD_EVENTCAUSE_RESUME_Msk);
+    NRF_USBD->EVENTCAUSE = evt_cause; // clear interrupt
 
-    if ( evt_cause & USBD_EVENTCAUSE_SUSPEND_Msk ) 
+    if ( evt_cause & USBD_EVENTCAUSE_SUSPEND_Msk )
     {
       dcd_event_bus_signal(0, DCD_EVENT_SUSPEND, true);
     }
-    
-    if ( evt_cause & USBD_EVENTCAUSE_RESUME_Msk  ) 
+
+    if ( evt_cause & USBD_EVENTCAUSE_RESUME_Msk  )
     {
       dcd_event_bus_signal(0, DCD_EVENT_RESUME , true);
     }
-
-    NRF_USBD->EVENTCAUSE = evt_cause; // clear interrupt
   }
 
   if ( int_status & EDPT_END_ALL_MASK )
@@ -397,7 +397,7 @@ void USBD_IRQHandler(void)
     // DMA complete move data from SRAM -> Endpoint
     edpt_dma_end();
   }
-
+ 
   // Setup tokens are specific to the Control endpoint.
   if ( int_status & USBD_INTEN_EP0SETUP_Msk )
   {