diff --git a/dmtree/tr181/ip.c b/dmtree/tr181/ip.c
index 7d8b71ba..1e29902f 100644
--- a/dmtree/tr181/ip.c
+++ b/dmtree/tr181/ip.c
@@ -1558,9 +1558,13 @@ static int set_IPInterface_Reset(char *refparam, struct dmctx *ctx, void *data,
 	return 0;
 }
 
-/*#Device.IP.Interface.{i}.MaxMTUSize!UCI:network/interface,@i-1/mtu*/
+/*#Device.IP.Interface.{i}.MaxMTUSize!SYSFS:/sys/class/net/@Name/mtu*/
 static int get_IPInterface_MaxMTUSize(char *refparam, struct dmctx *ctx, void *data, char *instance, char **value)
 {
+	get_ip_iface_sysfs(data, "mtu", value);
+	if (*value && **value != '0')
+		return 0;
+
 	*value = dmuci_get_value_by_section_fallback_def((struct uci_section *)data, "mtu", "1500");
 	return 0;
 }
diff --git a/json/tr181.json b/json/tr181.json
index 05c57fea..b987aa0b 100644
--- a/json/tr181.json
+++ b/json/tr181.json
@@ -41116,17 +41116,8 @@
 					],
 					"mapping": [
 						{
-							"type": "uci",
-							"uci": {
-								"file": "network",
-								"section": {
-									"type": "interface",
-									"index": "@i-1"
-								},
-								"option": {
-									"name": "mtu"
-								}
-							}
+							"type": "sysfs",
+							"file": "/sys/class/net/@Name/mtu"
 						}
 					]
 				},