diff --git a/ble_through/ble_proto_utils.h b/ble_through/ble_proto_utils.h
index cd1f0fb..df296bc 100644
--- a/ble_through/ble_proto_utils.h
+++ b/ble_through/ble_proto_utils.h
@@ -18,7 +18,7 @@ extern "C" {
     __data[packet->packetlen - 2] = ble_through_proto_sum(packet); \
   }
 
-#define BLE_THROUGH_PACKET_BASE_SIZE() (sizeof(zble_proto_packet_t) + 1)
+#define BLE_THROUGH_PACKET_BASE_SIZE() (sizeof(zble_proto_packet_t) + 2)
 
 bool    ble_through_proto_check_packet(zble_proto_packet_t *packet);
 uint8_t ble_through_proto_sum(zble_proto_packet_t *packet);