diff --git a/src/ble/gatt_client.c b/src/ble/gatt_client.c
index 2b6ffa367..a61fe02da 100644
--- a/src/ble/gatt_client.c
+++ b/src/ble/gatt_client.c
@@ -2321,7 +2321,7 @@ uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_
     gatt_client->callback = callback;
     gatt_client->start_group_handle = service->start_group_handle;
     gatt_client->end_group_handle   = service->end_group_handle;
-    gatt_client->filter_with_uuid = 0;
+    gatt_client->filter_with_uuid = false;
     gatt_client->characteristic_start_handle = 0;
     gatt_client->state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
     gatt_client_run();
@@ -2354,7 +2354,7 @@ uint8_t gatt_client_discover_characteristics_for_handle_range_by_uuid16(btstack_
     gatt_client->callback = callback;
     gatt_client->start_group_handle = start_handle;
     gatt_client->end_group_handle   = end_handle;
-    gatt_client->filter_with_uuid = 1;
+    gatt_client->filter_with_uuid = true;
     gatt_client->uuid16 = uuid16;
     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
     gatt_client->characteristic_start_handle = 0;
@@ -2373,7 +2373,7 @@ uint8_t gatt_client_discover_characteristics_for_handle_range_by_uuid128(btstack
     gatt_client->callback = callback;
     gatt_client->start_group_handle = start_handle;
     gatt_client->end_group_handle   = end_handle;
-    gatt_client->filter_with_uuid = 1;
+    gatt_client->filter_with_uuid = true;
     gatt_client->uuid16 = 0;
     (void)memcpy(gatt_client->uuid128, uuid128, 16);
     gatt_client->characteristic_start_handle = 0;
diff --git a/src/ble/gatt_client.h b/src/ble/gatt_client.h
index 28e14e1f7..73bffdfd0 100644
--- a/src/ble/gatt_client.h
+++ b/src/ble/gatt_client.h
@@ -236,7 +236,7 @@ typedef struct gatt_client{
     uint16_t client_characteristic_configuration_handle;
     uint8_t  client_characteristic_configuration_value[2];
     
-    uint8_t  filter_with_uuid;
+    bool     filter_with_uuid;
     uint8_t  send_confirmation;
 
     int      le_device_index;