--- a/master/device.c	Thu Oct 12 13:08:15 2017 +0200
+++ b/master/device.c	Thu Oct 12 13:09:52 2017 +0200
@@ -629,6 +629,8 @@
  * Forwards the received data to the master. The master will analyze the frame
  * and dispatch the received commands to the sending instances.
  *
+ * The data have to begin with the Ethernet header (target MAC address).
+ *
  * \ingroup DeviceInterface
  */
 void ecdev_receive(