Index: uspace/lib/nic/src/nic_driver.c
===================================================================
--- uspace/lib/nic/src/nic_driver.c	(revision 54a1ca73a9e9c3abb6bdcc1ae84ff0213fe6f721)
+++ uspace/lib/nic/src/nic_driver.c	(revision d4b63faf94a09dafd6012c7e11305a83ef0151e0)
@@ -47,4 +47,6 @@
 #include <ops/nic.h>
 #include <errno.h>
+
+#include <io/log.h>
 
 #include "nic_driver.h"
@@ -436,4 +438,6 @@
 		int rc = nic_ev_addr_changed(nic_data->client_session,
 		    address);
+		log_msg(LOG_DEFAULT, LVL_WARN, "rc=%d", rc);
+
 		if (rc != EOK) {
 			fibril_rwlock_write_unlock(&nic_data->main_lock);
Index: uspace/lib/nic/src/nic_impl.c
===================================================================
--- uspace/lib/nic/src/nic_impl.c	(revision 54a1ca73a9e9c3abb6bdcc1ae84ff0213fe6f721)
+++ uspace/lib/nic/src/nic_impl.c	(revision d4b63faf94a09dafd6012c7e11305a83ef0151e0)
@@ -179,4 +179,5 @@
 
 	nic_data->send_frame(nic_data, data, size);
+	fibril_rwlock_read_unlock(&nic_data->main_lock);
 	return EOK;
 }