diff --git a/core/usbd_core.c b/core/usbd_core.c
index e2ced33c45453cdb141ff1893f2a15e221988ffa..7eb634991ccae1af693f624af509ff90a2e59340 100644
--- a/core/usbd_core.c
+++ b/core/usbd_core.c
@@ -939,8 +939,18 @@ static void usbd_class_event_notify_handler(uint8_t event, void *arg)
     {
         struct usbd_interface *intf = usb_slist_entry(i, struct usbd_interface, list);
 
-        if (intf->notify_handler) {
-            intf->notify_handler(event, arg);
+        if (arg == NULL) {
+            if (intf->notify_handler) {
+                intf->notify_handler(event, arg);
+            }
+        }
+        else {
+            struct usb_interface_descriptor *intf_arg = (struct usb_interface_descriptor *)arg;
+            if (intf->intf_num == intf_arg->bInterfaceNumber) {
+                if (intf->notify_handler) {
+                    intf->notify_handler(event, arg);
+                }
+            }
         }
     }
 }
diff --git a/port/musb/usb_hc_musb.c b/port/musb/usb_hc_musb.c
index d55dc56147aa894a425791fd768be5870f68f5aa..51f47400b860fed689f90bbf324170ec3ed29fb3 100644
--- a/port/musb/usb_hc_musb.c
+++ b/port/musb/usb_hc_musb.c
@@ -921,6 +921,7 @@ void USBH_IRQHandler(void)
 
             pipe = &g_musb_hcd.pipe_pool[ep_idx][0];
             urb = pipe->urb;
+            if (urb == NULL) continue;
             musb_set_active_ep(ep_idx);
 
             ep_csrl_status = HWREGB(USB_BASE + MUSB_IND_TXCSRL_OFFSET);