diff --git a/cdl_utils/capdl_linker.py b/cdl_utils/capdl_linker.py
index 6bee81c..68b21f7 100644
--- a/cdl_utils/capdl_linker.py
+++ b/cdl_utils/capdl_linker.py
@@ -78,9 +78,8 @@ def final_spec(args, obj_space, cspaces, addr_spaces, targets, architecture):
 def main():
     parser = argparse.ArgumentParser(
         description="")
-    parser.add_argument('--architecture', '--arch', default='aarch32',
-                        type=lambda x: type('')(x).lower(), choices=valid_architectures(),
-                        help='Target architecture.')
+    parser.add_argument('--architecture', '--arch', required=True,
+                        choices=valid_architectures(), help='Target architecture.')
     parser.add_argument('--object-sizes', required=True, type=argparse.FileType('r'))
     subparsers = parser.add_subparsers()
     parser_a = subparsers.add_parser('build_cnode')