diff --git a/src/class/vendor/vendor_device.c b/src/class/vendor/vendor_device.c
index 62e183465d..a8c40557e7 100644
--- a/src/class/vendor/vendor_device.c
+++ b/src/class/vendor/vendor_device.c
@@ -166,6 +166,12 @@ uint32_t tud_vendor_n_write_available(uint8_t idx) {
   vendord_interface_t *p_itf = &_vendord_itf[idx];
   return tu_edpt_stream_write_available(p_itf->rhport, &p_itf->stream.tx);
 }
+#else
+bool tud_vendor_n_write_zlp_if_needed(uint8_t idx, uint32_t last_xferred_bytes) {
+  TU_VERIFY(idx < CFG_TUD_VENDOR, 0);
+  vendord_interface_t *p_itf = &_vendord_itf[idx];
+  return tu_edpt_stream_write_zlp_if_needed(p_itf->rhport, &p_itf->stream.tx, last_xferred_bytes);
+}
 #endif
 
 //--------------------------------------------------------------------+
diff --git a/src/class/vendor/vendor_device.h b/src/class/vendor/vendor_device.h
index 764d990702..80135aa06c 100644
--- a/src/class/vendor/vendor_device.h
+++ b/src/class/vendor/vendor_device.h
@@ -94,6 +94,9 @@ uint32_t tud_vendor_n_write_flush(uint8_t idx);
 
 // Return number of bytes available for writing in TX FIFO
 uint32_t tud_vendor_n_write_available(uint8_t idx);
+#else
+// TX FIFO disabled, write zlp manually.
+bool tud_vendor_n_write_zlp_if_needed(uint8_t idx, uint32_t last_xferred_bytes);
 #endif
 
 // Write a null-terminated string to TX FIFO
@@ -155,6 +158,10 @@ TU_ATTR_ALWAYS_INLINE static inline uint32_t tud_vendor_write_flush(void) {
 TU_ATTR_ALWAYS_INLINE static inline uint32_t tud_vendor_write_available(void) {
   return tud_vendor_n_write_available(0);
 }
+#else
+TU_ATTR_ALWAYS_INLINE static inline bool tud_vendor_write_zlp_if_needed(uint32_t last_xferred_bytes) {
+  return tud_vendor_n_write_zlp_if_needed(0, last_xferred_bytes);
+}
 #endif
 
 // backward compatible