diff --git a/doc/README.enetaddr b/doc/README.enetaddr
index 0fafd2c..82c9cd5 100644
--- a/doc/README.enetaddr
+++ b/doc/README.enetaddr
@@ -37,6 +37,8 @@
    environment variable will be used unchanged.
    If the environment variable is not set, it will be initialized from
    eth_device->enetaddr, and a warning will be printed.
+   If both are invalid and CONFIG_NET_RANDOM_ETHADDR is defined, a random,
+   locally-assigned MAC is written to eth_device->enetaddr.
 4. Program the address into hardware if the following conditions are met:
 	a) The relevant driver has a 'write_addr' function
 	b) The user hasn't set an 'ethmacskip' environment variable