diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 8c37336..a4f229e 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -681,7 +681,7 @@
 	}
 
 	/* errors aren't fatal - we can live with the dynamic address */
-	if (cdc_ether) {
+	if (cdc_ether && cdc_ether->wMaxSegmentSize) {
 		dev->hard_mtu = le16_to_cpu(cdc_ether->wMaxSegmentSize);
 		usbnet_get_ethernet_addr(dev, cdc_ether->iMACAddress);
 	}