diff --git a/examples/host/cdc_msc_hid/src/main.c b/examples/host/cdc_msc_hid/src/main.c
index 88d7cd4de..7f8b9d6e2 100644
--- a/examples/host/cdc_msc_hid/src/main.c
+++ b/examples/host/cdc_msc_hid/src/main.c
@@ -82,11 +82,14 @@ int main(void)
 // USB CDC
 //--------------------------------------------------------------------+
 #if CFG_TUH_CDC
+CFG_TUSB_MEM_SECTION static char serial_in_buffer[64] = { 0 };
 
 void tuh_cdc_mounted_cb(uint8_t dev_addr)
 {
   // application set-up
   printf("\na CDC device  (address %d) is mounted\n", dev_addr);
+
+  tuh_cdc_receive(dev_addr, serial_in_buffer, sizeof(serial_in_buffer), true); // schedule first transfer
 }
 
 void tuh_cdc_unmounted_cb(uint8_t dev_addr)
@@ -98,7 +101,10 @@ void tuh_cdc_unmounted_cb(uint8_t dev_addr)
 // invoked ISR context
 void tuh_cdc_xfer_isr(uint8_t dev_addr, xfer_result_t event, cdc_pipeid_t pipe_id, uint32_t xferred_bytes)
 {
+  printf(serial_in_buffer);
+  tu_memclr(serial_in_buffer, sizeof(serial_in_buffer));
 
+  tuh_cdc_receive(dev_addr, serial_in_buffer, sizeof(serial_in_buffer), true); // waiting for next data
 }
 
 void virtual_com_task(void)
diff --git a/examples/host/cdc_msc_hid/src/tusb_config.h b/examples/host/cdc_msc_hid/src/tusb_config.h
index b7a766796..ea411d3f4 100644
--- a/examples/host/cdc_msc_hid/src/tusb_config.h
+++ b/examples/host/cdc_msc_hid/src/tusb_config.h
@@ -82,10 +82,10 @@
 
 #define CFG_TUH_HUB               1 // not tested
 #define CFG_TUH_CDC               1
-#define CFG_TUH_HID_KEYBOARD      1
-#define CFG_TUH_HID_MOUSE         1
+#define CFG_TUH_HID_KEYBOARD      0
+#define CFG_TUH_HID_MOUSE         0
 #define CFG_TUSB_HOST_HID_GENERIC       0 // (not yet supported)
-#define CFG_TUH_MSC               1
+#define CFG_TUH_MSC               0
 
 #define CFG_TUSB_HOST_DEVICE_MAX        (CFG_TUH_HUB ? 5 : 1) // normal hub has 4 ports
 
diff --git a/src/class/cdc/cdc_host.h b/src/class/cdc/cdc_host.h
index 3252aa48d..13d7b710c 100644
--- a/src/class/cdc/cdc_host.h
+++ b/src/class/cdc/cdc_host.h
@@ -62,7 +62,7 @@
  * \retval      true if device supports
  * \retval      false if device does not support or is not mounted
  */
-bool tuh_cdc_serial_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+bool tuh_cdc_serial_is_mounted(uint8_t dev_addr);
 
 /** \brief      Check if the interface is currently busy or not
  * \param[in]   dev_addr device address
@@ -73,7 +73,7 @@ bool tuh_cdc_serial_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_WARN_UNUSED_RESU
  *              can be scheduled. User needs to make sure the corresponding interface is mounted
  *              (by \ref tuh_cdc_serial_is_mounted) before calling this function.
  */
-bool tuh_cdc_is_busy(uint8_t dev_addr, cdc_pipeid_t pipeid)  ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+bool tuh_cdc_is_busy(uint8_t dev_addr, cdc_pipeid_t pipeid);
 
 /** \brief 			Perform USB OUT transfer to device
  * \param[in]		dev_addr	device address