--- a/master/device.c	Thu Dec 23 09:48:56 2010 +0100
+++ b/master/device.c	Wed Jan 05 08:36:53 2011 +0100
@@ -501,9 +501,9 @@
     ec_mac_print(device->dev->dev_addr, str);
     EC_MASTER_INFO(master, "Releasing main device %s.\n", str);
     
-    down(&master->device_sem);
+    ec_mutex_lock(&master->device_mutex);
     ec_device_detach(device);
-    up(&master->device_sem);
+    ec_mutex_unlock(&master->device_mutex);
 }
 
 /*****************************************************************************/