diff --git a/src/class/net/net_device.h b/src/class/net/net_device.h
index 71483364..67cd9993 100644
--- a/src/class/net/net_device.h
+++ b/src/class/net/net_device.h
@@ -57,6 +57,7 @@ void tud_network_init_cb(void);
 bool tud_network_recv_cb(struct pbuf *p);
 
 // client must provide this: 48-bit MAC address
+// TODO removed later since it is not part of tinyusb stack
 extern const uint8_t tud_network_mac_address[6];
 
 // indicate to network driver that client has finished with the packet provided to network_recv_cb()