diff --git a/sys/include/usb/usbus.h b/sys/include/usb/usbus.h
index 1e5a8c727f..ec62f868d5 100644
--- a/sys/include/usb/usbus.h
+++ b/sys/include/usb/usbus.h
@@ -449,6 +449,15 @@ uint16_t usbus_add_string_descriptor(usbus_t *usbus, usbus_string_t *desc,
  */
 uint16_t usbus_add_interface(usbus_t *usbus, usbus_interface_t *iface);
 
+/**
+ * @brief Add alternate settings to a given interface
+ *
+ * @param[in] iface   USB interface
+ * @param[in] alt     alternate settings interface to add
+ */
+void usbus_add_interface_alt(usbus_interface_t *iface,
+                                 usbus_interface_alt_t *alt);
+
 /**
  * @brief Find an endpoint from an interface based on the endpoint properties
  *
diff --git a/sys/usb/usbus/cdc/ecm/cdc_ecm.c b/sys/usb/usbus/cdc/ecm/cdc_ecm.c
index f4da67efb9..f580209e03 100644
--- a/sys/usb/usbus/cdc/ecm/cdc_ecm.c
+++ b/sys/usb/usbus/cdc/ecm/cdc_ecm.c
@@ -229,7 +229,7 @@ static void _init(usbus_t *usbus, usbus_handler_t *handler)
     usbus_add_interface(usbus, &cdcecm->iface_ctrl);
     usbus_add_interface(usbus, &cdcecm->iface_data);
 
-    cdcecm->iface_data.alts = &cdcecm->iface_data_alt;
+    usbus_add_interface_alt(&cdcecm->iface_data, &cdcecm->iface_data_alt);
 
     usbus_enable_endpoint(cdcecm->ep_out);
     usbus_enable_endpoint(cdcecm->ep_in);
diff --git a/sys/usb/usbus/usbus.c b/sys/usb/usbus/usbus.c
index 84a5437e1b..8304134815 100644
--- a/sys/usb/usbus/usbus.c
+++ b/sys/usb/usbus/usbus.c
@@ -121,6 +121,16 @@ uint16_t usbus_add_interface(usbus_t *usbus, usbus_interface_t *iface)
     return idx;
 }
 
+void usbus_add_interface_alt(usbus_interface_t *iface,
+                             usbus_interface_alt_t *alt)
+{
+    usbus_interface_alt_t **last = &iface->alts;
+    while (*last) {
+        last = &(*last)->next;
+    }
+    *last = alt;
+}
+
 void usbus_register_event_handler(usbus_t *usbus, usbus_handler_t *handler)
 {
     /* See note above for reasons against clist.h */