diff --git a/var/spack/repos/builtin/packages/portcullis/package.py b/var/spack/repos/builtin/packages/portcullis/package.py
index aded91acdc0..20b20cfbd68 100644
--- a/var/spack/repos/builtin/packages/portcullis/package.py
+++ b/var/spack/repos/builtin/packages/portcullis/package.py
@@ -45,6 +45,11 @@ def patch(self):
             'scripts/Makefile.am', string=True
         )
 
+        # remove -m64 on aarch64
+        if self.spec.satisfies('target=aarch64'):
+            for f in ['lib/Makefile.am', 'src/Makefile.am']:
+                filter_file('-m64', '', f)
+
     def build(self, spec, prefix):
         # build manpages
         make('man')