diff -r a26dee45c467 -r 1aee02c1e294 master/ioctl.h
--- a/master/ioctl.h	Sat May 31 17:21:53 2014 +1200
+++ b/master/ioctl.h	Sat May 31 18:08:27 2014 +1200
@@ -400,7 +400,7 @@
     uint8_t sdo_entry_subindex;
     uint8_t complete_access;
     size_t data_size;
-    uint8_t *data;
+    const uint8_t *data;
 
     // outputs
     uint32_t abort_code;