diff --git a/README.rst b/README.rst
index 4cc62bd..aaef2fa 100644
--- a/README.rst
+++ b/README.rst
@@ -472,8 +472,8 @@
         MA==
         =dtMN
         -----END PGP PUBLIC KEY BLOCK-----
-      saltstack_repo_xenial: "http://${_param:local_repo_url}/ubuntu-xenial stable salt"
-      saltstack_repo_trusty: "http://${_param:local_repo_url}/ubuntu-trusty stable salt"
+      saltstack_repo_xenial: "deb [arch=amd64] http://${_param:local_repo_url}/ubuntu-xenial stable salt"
+      saltstack_repo_trusty: "deb [arch=amd64] http://${_param:local_repo_url}/ubuntu-trusty stable salt"
 
 Single MAAS cluster service [multiple racks]