diff --git a/bootstrap/cluster/main.tf b/bootstrap/cluster/main.tf
index 90528be..9b32d89 100644
--- a/bootstrap/cluster/main.tf
+++ b/bootstrap/cluster/main.tf
@@ -52,8 +52,8 @@ configure_debian_apt_https() {
 }
 
 diagnose_apt_network() {
-  local reason="${1:-APT package install failed}"
-  local packages="${2:-}"
+  local reason="$${1:-APT package install failed}"
+  local packages="$${2:-}"
 
   echo "$reason; checking APT state and mirror reachability..." >&2
   if [ -n "$packages" ]; then
@@ -610,8 +610,8 @@ configure_debian_apt_https() {
 }
 
 diagnose_apt_network() {
-  local reason="${1:-APT package install failed}"
-  local packages="${2:-}"
+  local reason="$${1:-APT package install failed}"
+  local packages="$${2:-}"
 
   echo "$reason; checking APT state and mirror reachability..." >&2
   if [ -n "$packages" ]; then