diff --git a/tests/lpc18xx_43xx/test/host/cdc/test_cdc_host.c b/tests/lpc18xx_43xx/test/host/cdc/test_cdc_host.c
index cd95f3fcd..8bd1d46b7 100644
--- a/tests/lpc18xx_43xx/test/host/cdc/test_cdc_host.c
+++ b/tests/lpc18xx_43xx/test/host/cdc/test_cdc_host.c
@@ -155,6 +155,39 @@ void test_cdch_open_acm_capacity_check(void)
   TEST_ASSERT_EQUAL_MEMORY(&cdc_config_descriptor.cdc_acm.bmCapabilities, &p_cdc->acm_capability, 1);
 }
 
+void test_cdch_close_device(void)
+{
+  pipe_handle_t pipe_notification = {
+      .dev_addr = 1,
+      .xfer_type = TUSB_XFER_INTERRUPT
+  };
+
+  pipe_handle_t pipe_out = {
+      .dev_addr  = 1,
+      .xfer_type = TUSB_XFER_BULK,
+      .index = 0
+  };
+
+  pipe_handle_t pipe_int = {
+      .dev_addr  = 1,
+      .xfer_type = TUSB_XFER_BULK,
+      .index = 1
+  };
+
+  hcd_pipe_open_ExpectAndReturn(dev_addr, p_endpoint_notification, TUSB_CLASS_CDC, pipe_notification);
+  hcd_pipe_open_ExpectAndReturn(dev_addr, p_endpoint_out, TUSB_CLASS_CDC, pipe_out);
+  hcd_pipe_open_ExpectAndReturn(dev_addr, p_endpoint_in, TUSB_CLASS_CDC, pipe_int);
+
+  TEST_ASSERT_EQUAL( TUSB_ERROR_NONE, cdch_open_subtask(dev_addr, p_comm_interface, &length) );
+
+  hcd_pipe_close_ExpectAndReturn(pipe_notification , TUSB_ERROR_NONE);
+  hcd_pipe_close_ExpectAndReturn(pipe_int          , TUSB_ERROR_NONE);
+  hcd_pipe_close_ExpectAndReturn(pipe_out          , TUSB_ERROR_NONE);
+
+  //------------- CUT -------------//
+  cdch_close(dev_addr);
+}
+
 
 
 
diff --git a/tinyusb/class/cdc_host.c b/tinyusb/class/cdc_host.c
index 9a3cb6ef8..ce1f67e20 100644
--- a/tinyusb/class/cdc_host.c
+++ b/tinyusb/class/cdc_host.c
@@ -57,6 +57,18 @@
 //--------------------------------------------------------------------+
 /*STATIC_*/ cdch_data_t cdch_data[TUSB_CFG_HOST_DEVICE_MAX];
 
+//--------------------------------------------------------------------+
+// APPLICATION API (parameter validation needed)
+//--------------------------------------------------------------------+
+bool tusbh_cdc_serial_is_mounted(uint8_t dev_addr)
+{
+  // TODO consider all AT Command as serial candidate
+  return
+      (tusbh_device_get_mounted_class_flag(dev_addr) & BIT_(TUSB_CLASS_CDC) )   &&
+      (CDC_COMM_PROTOCOL_ATCOMMAND <= cdch_data[dev_addr-1].interface_protocol) &&
+      (cdch_data[dev_addr-1].interface_protocol <= CDC_COMM_PROTOCOL_ATCOMMAND_CDMA);
+}
+
 //--------------------------------------------------------------------+
 // USBH-CLASS DRIVER API
 //--------------------------------------------------------------------+
diff --git a/tinyusb/class/cdc_host.h b/tinyusb/class/cdc_host.h
index 5eee3670b..2b39a6fd7 100644
--- a/tinyusb/class/cdc_host.h
+++ b/tinyusb/class/cdc_host.h
@@ -57,11 +57,11 @@
 //--------------------------------------------------------------------+
 // APPLICATION PUBLIC API
 //--------------------------------------------------------------------+
-bool tusbh_cdc_acm_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+//bool tusbh_cdc_acm_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
 bool tusbh_cdc_serial_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
 bool tusbh_cdc_rndis_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
 
-tusb_interface_status_t tusbh_cdc_send(void const * p_data, uint32_t length);
+tusb_interface_status_t tusbh_cdc_send(void const * p_data, uint32_t length, bool is_notify);
 
 //--------------------------------------------------------------------+
 // USBH-CLASS API
diff --git a/tinyusb/host/ehci/ehci.c b/tinyusb/host/ehci/ehci.c
index 97aaae680..3e75c265a 100644
--- a/tinyusb/host/ehci/ehci.c
+++ b/tinyusb/host/ehci/ehci.c
@@ -964,7 +964,7 @@ static ehci_link_t* list_find_previous_item(ehci_link_t* p_head, ehci_link_t* p_
   uint32_t max_loop = 0;
   while( (align32(p_prev->address) != (uint32_t) p_head)    && // not loop around
          (align32(p_prev->address) != (uint32_t) p_current) && // not found yet
-         !p_prev->terminate                                 && // not advancable
+         !p_prev->terminate                                 && // not advanceable
          max_loop < EHCI_MAX_QHD)
   {
     p_prev = list_next(p_prev);