diff --git a/main/usb_cdc.c b/main/usb_cdc.c
--- a/main/usb_cdc.c
+++ b/main/usb_cdc.c
@@ -31,8 +31,8 @@ static void __cdc_rx_callback(int itf, c
     }
 
     /* write back */
-    tinyusb_cdcacm_write_queue(itf, buf, rx_size);
-    tinyusb_cdcacm_write_flush(itf, 0);
+    //tinyusb_cdcacm_write_queue(itf, buf, rx_size);
+    //tinyusb_cdcacm_write_flush(itf, 0);
 }