diff --git a/tests/auc/gen_ts_55_205_test_sets/pdftxt_2_c.py b/tests/auc/gen_ts_55_205_test_sets/pdftxt_2_c.py
index 058113c..acc0f7d 100755
--- a/tests/auc/gen_ts_55_205_test_sets/pdftxt_2_c.py
+++ b/tests/auc/gen_ts_55_205_test_sets/pdftxt_2_c.py
@@ -1,5 +1,5 @@
-#!/usr/bin/env python
- 
+#!/usr/bin/python
+# FIXME: use python3 once buildslaves are updated.
 # Convert test sets pasted from 3GPP TS 55.205 to C code.
  
 # (C) 2016 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>