diff --git a/examples/device/webusb_serial/src/main.c b/examples/device/webusb_serial/src/main.c
index 800d435b8..bcc33f657 100644
--- a/examples/device/webusb_serial/src/main.c
+++ b/examples/device/webusb_serial/src/main.c
@@ -73,8 +73,7 @@ static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;
 
 #define URL  "example.tinyusb.org/webusb-serial/index.html"
 
-const tusb_desc_webusb_url_t desc_url =
-{
+const tusb_desc_webusb_url_t desc_url = {
   .bLength         = 3 + sizeof(URL) - 1,
   .bDescriptorType = 3, // WEBUSB URL type
   .bScheme         = 1, // 0: http, 1: https
@@ -86,11 +85,9 @@ static bool web_serial_connected = false;
 //------------- prototypes -------------//
 void led_blinking_task(void);
 void cdc_task(void);
-void webserial_task(void);
 
 /*------------- MAIN -------------*/
-int main(void)
-{
+int main(void) {
   board_init();
 
   // init device stack on configured roothub port
@@ -100,33 +97,28 @@ int main(void)
     board_init_after_tusb();
   }
 
-  while (1)
-  {
+  while (1) {
     tud_task(); // tinyusb device task
     cdc_task();
-    webserial_task();
     led_blinking_task();
   }
 }
 
 // send characters to both CDC and WebUSB
-void echo_all(uint8_t buf[], uint32_t count)
-{
+void echo_all(const uint8_t buf[], uint32_t count) {
   // echo to web serial
-  if ( web_serial_connected )
-  {
+  if (web_serial_connected) {
     tud_vendor_write(buf, count);
     tud_vendor_write_flush();
   }
 
   // echo to cdc
-  if ( tud_cdc_connected() )
-  {
-    for(uint32_t i=0; i<count; i++)
-    {
+  if (tud_cdc_connected()) {
+    for (uint32_t i = 0; i < count; i++) {
       tud_cdc_write_char(buf[i]);
-
-      if ( buf[i] == '\r' ) tud_cdc_write_char('\n');
+      if (buf[i] == '\r') {
+        tud_cdc_write_char('\n');
+      }
     }
     tud_cdc_write_flush();
   }
@@ -137,29 +129,25 @@ void echo_all(uint8_t buf[], uint32_t count)
 //--------------------------------------------------------------------+
 
 // Invoked when device is mounted
-void tud_mount_cb(void)
-{
+void tud_mount_cb(void) {
   blink_interval_ms = BLINK_MOUNTED;
 }
 
 // Invoked when device is unmounted
-void tud_umount_cb(void)
-{
+void tud_umount_cb(void) {
   blink_interval_ms = BLINK_NOT_MOUNTED;
 }
 
 // Invoked when usb bus is suspended
 // remote_wakeup_en : if host allow us  to perform remote wakeup
 // Within 7ms, device must draw an average of current less than 2.5 mA from bus
-void tud_suspend_cb(bool remote_wakeup_en)
-{
-  (void) remote_wakeup_en;
+void tud_suspend_cb(bool remote_wakeup_en) {
+  (void)remote_wakeup_en;
   blink_interval_ms = BLINK_SUSPENDED;
 }
 
 // Invoked when usb bus is resumed
-void tud_resume_cb(void)
-{
+void tud_resume_cb(void) {
   blink_interval_ms = tud_mounted() ? BLINK_MOUNTED : BLINK_NOT_MOUNTED;
 }
 
@@ -170,61 +158,53 @@ void tud_resume_cb(void)
 // Invoked when a control transfer occurred on an interface of this class
 // Driver response accordingly to the request and the transfer stage (setup/data/ack)
 // return false to stall control endpoint (e.g unsupported request)
-bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const * request)
-{
+bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_request_t const* request) {
   // nothing to with DATA & ACK stage
   if (stage != CONTROL_STAGE_SETUP) return true;
 
-  switch (request->bmRequestType_bit.type)
-  {
+  switch (request->bmRequestType_bit.type) {
     case TUSB_REQ_TYPE_VENDOR:
-      switch (request->bRequest)
-      {
+      switch (request->bRequest) {
         case VENDOR_REQUEST_WEBUSB:
           // match vendor request in BOS descriptor
           // Get landing page url
-          return tud_control_xfer(rhport, request, (void*)(uintptr_t) &desc_url, desc_url.bLength);
+          return tud_control_xfer(rhport, request, (void*)(uintptr_t)&desc_url, desc_url.bLength);
 
         case VENDOR_REQUEST_MICROSOFT:
-          if ( request->wIndex == 7 )
-          {
+          if (request->wIndex == 7) {
             // Get Microsoft OS 2.0 compatible descriptor
             uint16_t total_len;
-            memcpy(&total_len, desc_ms_os_20+8, 2);
+            memcpy(&total_len, desc_ms_os_20 + 8, 2);
 
-            return tud_control_xfer(rhport, request, (void*)(uintptr_t) desc_ms_os_20, total_len);
-          }else
-          {
+            return tud_control_xfer(rhport, request, (void*)(uintptr_t)desc_ms_os_20, total_len);
+          } else {
             return false;
           }
 
         default: break;
       }
-    break;
+      break;
 
     case TUSB_REQ_TYPE_CLASS:
-      if (request->bRequest == 0x22)
-      {
+      if (request->bRequest == 0x22) {
         // Webserial simulate the CDC_REQUEST_SET_CONTROL_LINE_STATE (0x22) to connect and disconnect.
         web_serial_connected = (request->wValue != 0);
 
         // Always lit LED if connected
-        if ( web_serial_connected )
-        {
+        if (web_serial_connected) {
           board_led_write(true);
           blink_interval_ms = BLINK_ALWAYS_ON;
 
           tud_vendor_write_str("\r\nWebUSB interface connected\r\n");
           tud_vendor_write_flush();
-        }else
-        {
+        } else {
           blink_interval_ms = BLINK_MOUNTED;
         }
 
         // response with status OK
         return tud_control_status(rhport, request);
       }
-    break;
+      break;
 
     default: break;
   }
@@ -233,32 +213,24 @@ bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb_control_requ
   return false;
 }
 
-void webserial_task(void)
-{
-  if ( web_serial_connected )
-  {
-    if ( tud_vendor_available() )
-    {
-      uint8_t buf[64];
-      uint32_t count = tud_vendor_read(buf, sizeof(buf));
+void tud_vendor_rx_cb(uint8_t itf, uint8_t const* buffer, uint16_t bufsize) {
+  (void) itf;
 
-      // echo back to both web serial and cdc
-      echo_all(buf, count);
-    }
-  }
+  echo_all(buffer, bufsize);
+
+  // if using RX buffered is enabled, we need to flush the buffer to make room for new data
+  #if CFG_TUD_VENDOR_RX_BUFSIZE > 0
+  tud_vendor_read_flush();
+  #endif
 }
 
-
 //--------------------------------------------------------------------+
 // USB CDC
 //--------------------------------------------------------------------+
-void cdc_task(void)
-{
-  if ( tud_cdc_connected() )
-  {
+void cdc_task(void) {
+  if (tud_cdc_connected()) {
     // connected and there are data available
-    if ( tud_cdc_available() )
-    {
+    if (tud_cdc_available()) {
       uint8_t buf[64];
 
       uint32_t count = tud_cdc_read(buf, sizeof(buf));
@@ -270,34 +242,30 @@ void cdc_task(void)
 }
 
 // Invoked when cdc when line state changed e.g connected/disconnected
-void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts)
-{
-  (void) itf;
+void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
+  (void)itf;
 
   // connected
-  if ( dtr && rts )
-  {
+  if (dtr && rts) {
     // print initial message when connected
     tud_cdc_write_str("\r\nTinyUSB WebUSB device example\r\n");
   }
 }
 
 // Invoked when CDC interface received data from host
-void tud_cdc_rx_cb(uint8_t itf)
-{
-  (void) itf;
+void tud_cdc_rx_cb(uint8_t itf) {
+  (void)itf;
 }
 
 //--------------------------------------------------------------------+
 // BLINKING TASK
 //--------------------------------------------------------------------+
-void led_blinking_task(void)
-{
+void led_blinking_task(void) {
   static uint32_t start_ms = 0;
   static bool led_state = false;
 
   // Blink every interval ms
-  if ( board_millis() - start_ms < blink_interval_ms) return; // not enough time
+  if (board_millis() - start_ms < blink_interval_ms) return; // not enough time
   start_ms += blink_interval_ms;
 
   board_led_write(led_state);
diff --git a/examples/device/webusb_serial/src/tusb_config.h b/examples/device/webusb_serial/src/tusb_config.h
index fde732b9e..b86ad3752 100644
--- a/examples/device/webusb_serial/src/tusb_config.h
+++ b/examples/device/webusb_serial/src/tusb_config.h
@@ -102,7 +102,7 @@
 #define CFG_TUD_CDC_TX_BUFSIZE    (TUD_OPT_HIGH_SPEED ? 512 : 64)
 
 // Vendor FIFO size of TX and RX
-// If not configured vendor endpoints will not be buffered
+// If zero: vendor endpoints will not be buffered
 #define CFG_TUD_VENDOR_RX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
 #define CFG_TUD_VENDOR_TX_BUFSIZE (TUD_OPT_HIGH_SPEED ? 512 : 64)
 
diff --git a/src/common/tusb_private.h b/src/common/tusb_private.h
index 71a395c79..ce42d7ef6 100644
--- a/src/common/tusb_private.h
+++ b/src/common/tusb_private.h
@@ -34,29 +34,24 @@
  extern "C" {
 #endif
 
-typedef struct TU_ATTR_PACKED
-{
+typedef struct TU_ATTR_PACKED {
   volatile uint8_t busy    : 1;
   volatile uint8_t stalled : 1;
   volatile uint8_t claimed : 1;
 }tu_edpt_state_t;
 
 typedef struct {
-  struct {
-      uint8_t is_host : 1;       // host or device
-      uint8_t is_highspeed: 1;       // is highspeed
-  };
+  uint8_t is_host; // 1: host, 0: device
   uint8_t ep_addr;
 
   uint16_t ep_packetsize;
   uint16_t ep_bufsize;
 
-  // TODO xfer_fifo can skip this buffer
-  uint8_t* ep_buf;
+  uint8_t* ep_buf; // TODO xfer_fifo can skip this buffer
 
   tu_fifo_t ff;
 
-  // mutex: read if ep rx, write if e tx
+  // mutex: read if rx, otherwise write
   OSAL_MUTEX_DEF(ff_mutexdef);
 
 }tu_edpt_stream_t;
@@ -92,7 +87,6 @@ bool tu_edpt_stream_init(tu_edpt_stream_t* s, bool is_host, bool is_tx, bool ove
 bool tu_edpt_stream_deinit(tu_edpt_stream_t* s);
 
 // Open an stream for an endpoint
-// hwid is either device address (host mode) or rhport (device mode)
 TU_ATTR_ALWAYS_INLINE static inline
 void tu_edpt_stream_open(tu_edpt_stream_t* s, tusb_desc_endpoint_t const *desc_ep) {
   tu_fifo_clear(&s->ff);