diff --git a/luci-app-openmptcprouter/luasrc/view/openmptcprouter/wizard.htm b/luci-app-openmptcprouter/luasrc/view/openmptcprouter/wizard.htm
index 7fc7ad7b8..0d715c027 100644
--- a/luci-app-openmptcprouter/luasrc/view/openmptcprouter/wizard.htm
+++ b/luci-app-openmptcprouter/luasrc/view/openmptcprouter/wizard.htm
@@ -46,12 +46,14 @@
 
 	alltty = {}
 	iftty = luci.sys.exec("timeout 1 /usr/bin/mmcli -L")
-	for listtty in iftty:gmatch("([^\r\n]*)[\r\n]") do
-		modemid = luci.util.trim(luci.sys.exec("echo '" .. listtty .. "' | awk -F' ' '{print $1}' | awk -F/ '{print $6}'"))
-		if modemid ~= '' then
-			modeminfo = luci.sys.exec("timeout 1 /usr/bin/mmcli -m " .. modemid .. " --output-keyvalue")
-			tty = luci.util.trim(luci.sys.exec("echo '" .. modeminfo .. "' | grep 'modem.generic.device ' | awk -F': ' '{print $2}'"))
-			table.insert(alltty, tty)
+	if iftty ~= nil then
+		for listtty in iftty:gmatch("([^\r\n]*)[\r\n]") do
+			modemid = luci.util.trim(luci.sys.exec("echo '" .. listtty .. "' | awk -F' ' '{print $1}' | awk -F/ '{print $6}'"))
+			if modemid ~= '' then
+				modeminfo = luci.sys.exec("timeout 1 /usr/bin/mmcli -m " .. modemid .. " --output-keyvalue")
+				tty = luci.util.trim(luci.sys.exec("echo '" .. modeminfo .. "' | grep 'modem.generic.device ' | awk -F': ' '{print $2}'"))
+				table.insert(alltty, tty)
+			end
 		end
 	end