diff -r 291dddb7233e -r a5c9005fe7a8 master/slave_config.c
--- a/master/slave_config.c	Fri Jan 22 10:11:58 2016 +0100
+++ b/master/slave_config.c	Fri Sep 16 11:56:10 2016 +0200
@@ -714,9 +714,9 @@
                 if (ret)
                     return ret;
 
+                ecrt_slave_config_pdo_mapping_clear(sc, pdo_info->index);
+
                 if (pdo_info->n_entries && pdo_info->entries) {
-                    ecrt_slave_config_pdo_mapping_clear(sc, pdo_info->index);
-
                     for (k = 0; k < pdo_info->n_entries; k++) {
                         entry_info = &pdo_info->entries[k];