diff --git a/os_builders/roles/nubes_bootcontext/files/update_cloud_users.sh b/os_builders/roles/nubes_bootcontext/files/update_cloud_users.sh
index 19f7d3c1..09da7092 100644
--- a/os_builders/roles/nubes_bootcontext/files/update_cloud_users.sh
+++ b/os_builders/roles/nubes_bootcontext/files/update_cloud_users.sh
@@ -4,16 +4,11 @@ set -euxo pipefail
 
 mkdir -p /mnt/context
 if [[ ! -d "/mnt/context/openstack" ]]; then
-    mount /dev/sro /mnt/context
+    mount /dev/sr0 /mnt/context
 fi
 
 INSTANCEID=$(jq -r .uuid /mnt/context/openstack/latest/meta_data.json)
 
-# fallback to dmidecode if needed
-if [[ -z "$INSTANCEID" ]]; then
-    INSTANCEID=$(dmidecode | awk -F': ' '/UUID/ {print tolower($2)}')
-fi
-
 BASE_URLS=(
     "https://openstack.stfc.ac.uk"
     "https://dev-openstack.stfc.ac.uk"