diff --git a/erlang/rebar.config b/erlang/rebar.config
index 95fa370..cebc643 100644
--- a/erlang/rebar.config
+++ b/erlang/rebar.config
@@ -63,6 +63,7 @@
   , {scan, format_error, 1}
   , {scan_state, format_error, 1}
   , {sim, format_error, 1}
+  , {sim_loader, format_error, 1}
   , {strtol, format_error, 1}
     %% actual unused exports
   , {pdp10_opcodes, cpu_device_from_name, 2}