diff --git a/hardware/hantek-dso/api.c b/hardware/hantek-dso/api.c
index 9e5629ee..fd4f6157 100644
--- a/hardware/hantek-dso/api.c
+++ b/hardware/hantek-dso/api.c
@@ -409,12 +409,10 @@ static int config_get(int id, GVariant **data, const struct sr_dev_inst *sdi)
 	struct sr_usb_dev_inst *usb;
 	char str[128];
 
-	(void)sdi;
-
 	switch (id) {
 	case SR_CONF_CONN:
 		if (!sdi || !sdi->conn)
-			return SR_ERR;
+			return SR_ERR_ARG;
 		usb = sdi->conn;
 		if (usb->address == 255)
 			/* Device still needs to re-enumerate after firmware