diff --git a/master/fsm_slave_scan.c b/master/fsm_slave_scan.c
index bf514322..7bc3a393 100644
--- a/master/fsm_slave_scan.c
+++ b/master/fsm_slave_scan.c
@@ -682,9 +682,8 @@ void ec_fsm_slave_scan_state_sii_data(ec_fsm_slave_scan_t *fsm /**< slave state
                     goto end;
                 break;
             default:
-                if (fsm->slave->master->debug_level)
-                    EC_SLAVE_WARN(slave, "Unknown category type 0x%04X.\n",
-                            cat_type);
+                EC_SLAVE_DBG(slave, 1, "Unknown category type 0x%04X.\n",
+                        cat_type);
         }
 
         cat_word += cat_size;
diff --git a/master/slave.c b/master/slave.c
index bf53b9ca..7a0ec9ab 100644
--- a/master/slave.c
+++ b/master/slave.c
@@ -581,8 +581,7 @@ char *ec_slave_sii_string(
         return NULL;
 
     if (index >= slave->sii.string_count) {
-        if (slave->master->debug_level)
-            EC_SLAVE_WARN(slave, "String %u not found.\n", index);
+        EC_SLAVE_DBG(slave, 1, "String %u not found.\n", index);
         return NULL;
     }