diff --git a/src/x86_64/Gis_signal_frame.c b/src/x86_64/Gis_signal_frame.c
index c9bab906..b795827c 100644
--- a/src/x86_64/Gis_signal_frame.c
+++ b/src/x86_64/Gis_signal_frame.c
@@ -54,8 +54,8 @@ unw_is_signal_frame (unw_cursor_t *cursor)
   if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0
       || (ret = (*a->access_mem) (as, ip + 8, &w1, 0, arg)) < 0)
     return 0;
-  w1 &= 0xffffffff;
-  return (w0 == 0x0f0000000fc0c748 && w1 == 0x66666605);
+  w1 &= 0xff;
+  return (w0 == 0x0f0000000fc0c748 && w1 == 0x05);
 }
 
 #else /* __linux__ */