Index: src/OFMessagePackExtension.m
==================================================================
--- src/OFMessagePackExtension.m
+++ src/OFMessagePackExtension.m
@@ -122,11 +122,11 @@
 		ret = [OFDataArray dataArrayWithCapacity: count + 4];
 
 		prefix = 0xC8;
 		[ret addItem: &prefix];
 
-		length = OF_BSWAP16((uint16_t)count);
+		length = OF_BSWAP16_IF_LE((uint16_t)count);
 		[ret addItems: &length
 			count: 2];
 
 		[ret addItem: &_type];
 	} else {
@@ -135,11 +135,11 @@
 		ret = [OFDataArray dataArrayWithCapacity: count + 6];
 
 		prefix = 0xC9;
 		[ret addItem: &prefix];
 
-		length = OF_BSWAP32((uint32_t)count);
+		length = OF_BSWAP32_IF_LE((uint32_t)count);
 		[ret addItems: &length
 			count: 4];
 
 		[ret addItem: &_type];
 	}