add --no-check-certificate so that document procedure works
diff --git a/tools/xen/README.md b/tools/xen/README.md
index 3e28182..97e8839 100644
--- a/tools/xen/README.md
+++ b/tools/xen/README.md
@@ -23,7 +23,7 @@
 At this point, your server is missing some critical software that you will
 need to run devstack (like git).  Do this to install required software:
 
-    wget https://github.com/cloudbuilders/devstack/raw/xen/tools/xen/prepare_dom0.sh
+    wget --no-check-certificate https://github.com/cloudbuilders/devstack/raw/xen/tools/xen/prepare_dom0.sh
     chmod 755 prepare_dom0.sh
     ./prepare_dom0.sh