diff --git a/mkconfig.bash b/mkconfig.bash
index ec9abc5..6b15db8 100755
--- a/mkconfig.bash
+++ b/mkconfig.bash
@@ -88,14 +88,15 @@ if ! [ -f "architectures/$cfg_architecture.cfg" ]; then
 fi
 source "architectures/$cfg_architecture.cfg"
 
-# Creating the mac address if not set in configuration file we create one derivated from the IP address:
-if [ -n $cfg_eth_ext_ip ]; then
-  ips=(`echo $cfg_eth_ext_ip | sed -e 's/\./\n/g'`)
-  for i in "${ips[@]}"
-  do
-    hip=("${hip[@]}" `printf '%x' $i`)
-  done
-  cfg_eth_ext_mac="80:c1:${hip[0]}:${hip[1]}:${hip[2]}:${hip[3]}"
+# Create a MAC address based on the IP address if cfg_eth_ext_soft_mac
+# is set.
+if [ -n "$cfg_eth_ext_ip" ] && [ -n "$cfg_eth_ext_soft_mac" ]; then
+    ips=(`echo $cfg_eth_ext_ip | sed -e 's/\./\n/g'`)
+    for i in "${ips[@]}"
+    do
+        hip=("${hip[@]}" `printf '%x' $i`)
+    done
+    cfg_eth_ext_mac="80:c1:${hip[0]}:${hip[1]}:${hip[2]}:${hip[3]}"
 fi
 
 # Config: system name.
diff --git a/systems/lctr-a9xx/config b/systems/lctr-a9xx/config
index 3621581..e6b752b 100644
--- a/systems/lctr-a9xx/config
+++ b/systems/lctr-a9xx/config
@@ -11,6 +11,7 @@ cfg_ntpd_config='/etc/ntp/server.cfg'
 cfg_dtnd_config='/opt/lsts/dtn/etc/dtn.conf'
 cfg_eth_ext_mk='255.255.0.0'
 cfg_eth_ext_gw='10.0.0.1'
+cfg_eth_ext_soft_mac='true'
 cfg_target_uboot_config='igep0020_config'
 cfg_target_linux_load_addr=0x80008000
 cfg_partitions=\