From 978a79d369b2d0b1670e783c7e3856f7388dffcf Mon Sep 17 00:00:00 2001
From: Toby Gray <toby.gray@gmail.com>
Date: Tue, 10 Apr 2018 19:38:36 +0100
Subject: [PATCH] device_tracker.ubus: Handle devices not running DHCP (#13579)

---
 homeassistant/components/device_tracker/ubus.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/homeassistant/components/device_tracker/ubus.py b/homeassistant/components/device_tracker/ubus.py
index dd12df7b070..3d7ef5cef6e 100644
--- a/homeassistant/components/device_tracker/ubus.py
+++ b/homeassistant/components/device_tracker/ubus.py
@@ -103,6 +103,9 @@ class UbusDeviceScanner(DeviceScanner):
         """Return the name of the given device or None if we don't know."""
         if self.mac2name is None:
             self._generate_mac2name()
+        if self.mac2name is None:
+            # Generation of mac2name dictionary failed
+            return None
         name = self.mac2name.get(device.upper(), None)
         return name