diff --git a/src/copapy/__init__.py b/src/copapy/__init__.py
index 7cc15a7..79e6c2a 100644
--- a/src/copapy/__init__.py
+++ b/src/copapy/__init__.py
@@ -442,7 +442,7 @@ def compile_to_instruction_list(node_list: Iterable[Node], sdb: stencil_database
 
     # write program data
     dw.write_com(binw.Command.COPY_CODE)
-    dw.write_int(0)
+    dw.write_int(aux_function_lengths)
     dw.write_int(offset)
     dw.write_bytes(b''.join(data_list))