diff --git a/misc-scripts/xref_mapping/XrefParser/ChecksumParser.pm b/misc-scripts/xref_mapping/XrefParser/ChecksumParser.pm
index 15dafdb8a6edbab5c03284a7cb0dea535ce709bd..29d26cfc645a49cfcf1d77c2a99f9e3adaf26af4 100644
--- a/misc-scripts/xref_mapping/XrefParser/ChecksumParser.pm
+++ b/misc-scripts/xref_mapping/XrefParser/ChecksumParser.pm
@@ -47,6 +47,7 @@ sub run {
   }
   $verbose ||=0;
 
+  # FIXME: this will fail if the input file is in a read-only directory (ENSCORESW-3197)
   my $target_file = $files->[0].'.mysqlinput';
   my $input_fh = $self->get_filehandle($files->[0]);
   if(-f $target_file) {