diff --git a/dist/tools/ethos/start_network.sh b/dist/tools/ethos/start_network.sh
index 7b7378994e68..0746d8c32ce4 100755
--- a/dist/tools/ethos/start_network.sh
+++ b/dist/tools/ethos/start_network.sh
@@ -42,6 +42,7 @@ PORT=$1
 TAP=$2
 PREFIX=$3
 BAUDRATE=115200
+START_ETHOS=1
 
 [ -z "${PORT}" -o -z "${TAP}" -o -z "${PREFIX}" ] && {
     echo "usage: $0 [-e|--ethos-only] <serial-port> <tap-device> <prefix> " \
diff --git a/dist/tools/sliptty/start_network.sh b/dist/tools/sliptty/start_network.sh
index 51543d2f97ff..3856f044a8a1 100755
--- a/dist/tools/sliptty/start_network.sh
+++ b/dist/tools/sliptty/start_network.sh
@@ -6,6 +6,7 @@ TUN=sl0
 TUN_GLB="fdea:dbee:f::1/64"
 UHCPD_PID=
 CREATED_IFACE=0
+START_SLIP=1
 
 SUDO=${SUDO:-sudo}