diff --git a/script/ethercat.conf b/script/ethercat.conf
index 84b2a08b..4fd1d60b 100644
--- a/script/ethercat.conf
+++ b/script/ethercat.conf
@@ -4,10 +4,12 @@
 #
 #  $Id$
 #
+#  vim: spelllang=en spell tw=78
+#
 #------------------------------------------------------------------------------
 
 #
-# Master devices.
+# Main Ethernet devices.
 #
 # The MASTER<X>_DEVICE variable specifies the Ethernet device for a master
 # with index 'X'.
@@ -25,6 +27,15 @@
 MASTER0_DEVICE=""
 #MASTER1_DEVICE=""
 
+#
+# Backup Ethernet devices
+#
+# The MASTER<X>_BACKUP variables specify the devices used for redundancy. They
+# behaves nearly the same as the MASTER<X>_DEVICE variable, except that it
+# does not interpret the ff:ff:ff:ff:ff:ff address.
+#
+#MASTER0_BACKUP=""
+
 #
 # Ethernet driver modules to use for EtherCAT operation.
 #
@@ -42,6 +53,10 @@ MASTER0_DEVICE=""
 # Note: The e100, e1000, e1000e and r8169 drivers are not built by default.
 # Enable them with the --enable-<driver> configure switches.
 #
+# Attention: When using the generic driver, the corresponding Ethernet device
+# has to be activated (with OS methods, for example 'ip link set ethX up'),
+# before the master is started, otherwise all frames will time out.
+#
 DEVICE_MODULES=""
 
 #
diff --git a/script/sysconfig/ethercat b/script/sysconfig/ethercat
index 6dcc974b..9f45148b 100644
--- a/script/sysconfig/ethercat
+++ b/script/sysconfig/ethercat
@@ -53,6 +53,10 @@ MASTER0_DEVICE=""
 # Note: The e100, e1000, e1000e and r8169 drivers are not built by default.
 # Enable them with the --enable-<driver> configure switches.
 #
+# Attention: When using the generic driver, the corresponding Ethernet device
+# has to be activated (with OS methods, for example 'ip link set ethX up'),
+# before the master is started, otherwise all frames will time out.
+#
 DEVICE_MODULES=""
 
 #