diff --git a/slsReceiverSoftware/include/receiver_defs.h b/slsReceiverSoftware/include/receiver_defs.h
index 2fabca0bd..bab8edfda 100755
--- a/slsReceiverSoftware/include/receiver_defs.h
+++ b/slsReceiverSoftware/include/receiver_defs.h
@@ -21,7 +21,9 @@
 #define FILE_BUFFER_SIZE        		(16*1024*1024) //16mb
 
 //fifo
-#define FIFO_HEADER_NUMBYTES			4
+#define FIFO_HEADER_NUMBYTES			8
+#define FIFO_DATASIZE_NUMBYTES          4
+#define FIFO_PADDING_NUMBYTES           4 // for 8 byte alignment due to sls_receiver_header structure
 
 
 //hdf5