diff --git a/ccnode/host/tags.py b/ccnode/host/tags.py
index 8d57532cb09896e8f1a6348037c3146e703c5bd1..f99f9ca1831cb7d11b7bce7e5ce96ecdb77503d7 100644
--- a/ccnode/host/tags.py
+++ b/ccnode/host/tags.py
@@ -29,8 +29,7 @@ def arch():
         u'i586': u'x86',
         u'i686': u'x86',
         u'x86_64': u'x64',
-        u'': None,
-    }[platform_.machine()]
+    }.get(platform_.machine(), u'unknown')
 
 
 def cpu():