diff --git a/package/utils/otrx/src/otrx.c b/package/utils/otrx/src/otrx.c
index 131d8d6052..101a31004d 100644
--- a/package/utils/otrx/src/otrx.c
+++ b/package/utils/otrx/src/otrx.c
@@ -18,6 +18,10 @@
 #include <string.h>
 #include <unistd.h>
 
+#if !defined(__BYTE_ORDER)
+#error "Unknown byte order"
+#endif
+
 #if __BYTE_ORDER == __BIG_ENDIAN
 #define cpu_to_le32(x)	bswap_32(x)
 #define le32_to_cpu(x)	bswap_32(x)