diff --git a/user-data.sh.tftpl b/user-data.sh.tftpl
index fba06e7..b682487 100644
--- a/user-data.sh.tftpl
+++ b/user-data.sh.tftpl
@@ -134,7 +134,7 @@ write_final_config() {
               fi
 
               install -m 0644 "$user_data" /etc/nixos/flake.nix
-              ${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch --flake /etc/nixos
+              $${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch --flake /etc/nixos
               printf '%s\n' "$new_hash" > "$applied_hash_file"
             '';
           };