diff --git a/scripts/check-installed-state.sh b/scripts/check-installed-state.sh
index 8bde0581..9331f63c 100755
--- a/scripts/check-installed-state.sh
+++ b/scripts/check-installed-state.sh
@@ -37,7 +37,7 @@ config_ref=${values[2]}
 
 if [[ "$config_repository" =~ ^[A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+$ ]]; then
   [[ -x "$remote_reconciler" ]] || { echo "ERROR: remote reconciler is unavailable: $remote_reconciler" >&2; exit 2; }
-  CI_FLEET_REMOTE_STATE_FILE="$state_file" exec "$remote_reconciler" --check-only --desired-ref "$config_ref"
+  CI_FLEET_REMOTE_STATE_FILE="$state_file" exec "$remote_reconciler" --check-only --installed-ref
 fi
 
 exec "$installer" --check \
diff --git a/scripts/remote-reconcile.sh b/scripts/remote-reconcile.sh
index e615d185..a4b5bb16 100755
--- a/scripts/remote-reconcile.sh
+++ b/scripts/remote-reconcile.sh
@@ -6,7 +6,7 @@
 # validates the configuration, checks for drift, and reconciles if needed.
 #
 # Usage:
-#   remote-reconcile.sh [--check-only] [--desired-ref SHA] [--no-op]
+#   remote-reconcile.sh [--check-only] [--installed-ref] [--no-op]
 set -Eeuo pipefail
 
 script_dir=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
@@ -26,19 +26,21 @@ trap cleanup_temp EXIT
 
 mode=reconcile  # reconcile or check-only
 no_op=false
-desired_ref=
+installed_ref=false
 max_attempts=${CI_FLEET_RECONCILE_MAX_ATTEMPTS:-3}
+# ponytail: one-hour queue cap; align with any future installer transaction timeout.
+lock_wait_seconds=3600
 
 usage() {
   cat >&2 <<'EOF'
 usage:
-  remote-reconcile.sh [--check-only] [--desired-ref SHA] [--no-op]
+  remote-reconcile.sh [--check-only] [--installed-ref] [--no-op]
 
   Fetches the desired-state repository at the current default-branch HEAD,
   validates it, and reconciles the controller if a newer commit is available.
 
   --check-only  Validate and report without reconciling.
-  --desired-ref Check this exact commit instead of remote HEAD (check-only only).
+  --installed-ref Check the locked installation's commit (check-only only).
   --no-op       Log what would be done without side effects.
 EOF
 }
@@ -46,15 +48,14 @@ EOF
 while (($#)); do
   case "$1" in
     --check-only) mode=check-only ;;
-    --desired-ref) shift; (($#)) || { echo 'ERROR: --desired-ref requires a commit' >&2; exit 2; }; desired_ref=$1 ;;
+    --installed-ref) installed_ref=true ;;
     --no-op) no_op=true ;;
     -h|--help) usage; exit 0 ;;
     *) echo "ERROR: unknown argument: $1" >&2; usage; exit 2 ;;
   esac
   shift
 done
-[[ -z "$desired_ref" || "$mode" == check-only ]] || { echo 'ERROR: --desired-ref requires --check-only' >&2; exit 2; }
-[[ -z "$desired_ref" || "$desired_ref" =~ ^[0-9a-f]{40}$ ]] || { echo 'ERROR: --desired-ref must be a full lowercase commit SHA' >&2; exit 2; }
+[[ "$installed_ref" == false || "$mode" == check-only ]] || { echo 'ERROR: --installed-ref requires --check-only' >&2; exit 2; }
 
 note() { printf 'RECONCILE %s\n' "$*"; }
 die() {
@@ -322,10 +323,13 @@ require_commands
 lock_file=${CI_FLEET_INSTALLER_LOCK:-/run/ci-fleet-installer.lock}
 install -d -m 0755 "$(dirname "$lock_file")"
 exec 9>"$lock_file"
-flock -n 9 || die "another reconcile or installer is already running"
+flock -w "$lock_wait_seconds" 9 || die "timed out waiting for another reconcile or installer"
 
 # Load installed state
 load_installed_state || die "no installed state found at $state_file"
+[[ "$installed_config_ref" =~ ^[0-9a-f]{40}$ ]] || die "installed config ref is not a full lowercase commit SHA"
+fetch_ref=HEAD
+[[ "$installed_ref" == false ]] || fetch_ref=$installed_config_ref
 note "INSTALLED controller=${installed_controller} config_repo=${installed_config_repo} config_ref=${installed_config_ref}"
 
 # Prefer host.env for token generation; fall back to rendered_env
@@ -354,7 +358,7 @@ while ((attempt < max_attempts)); do
 
   # Fetch remote config
   note "FETCHING_CONFIG repo=${installed_config_repo}"
-  desired_commit=$(fetch_remote_config "$installed_config_repo" "$token" "${desired_ref:-HEAD}") || {
+  desired_commit=$(fetch_remote_config "$installed_config_repo" "$token" "$fetch_ref") || {
     note "FETCH_FAILED attempt=${attempt}"
     ((attempt < max_attempts)) && { sleep 5; continue; }
     die "fetch exhausted after ${max_attempts} attempts"
diff --git a/scripts/test-install-worker-controller.sh b/scripts/test-install-worker-controller.sh
index 4e34c07f..6cfc4af6 100755
--- a/scripts/test-install-worker-controller.sh
+++ b/scripts/test-install-worker-controller.sh
@@ -331,7 +331,7 @@ with open(path, "w") as output:
 PY
 expect_success env CI_FLEET_INSTALL_STATE_FILE="$install_state" CI_FLEET_INSTALLER="$installer" CI_FLEET_REMOTE_RECONCILER="$remote_reconciler" REMOTE_RECONCILER_LOG="$remote_reconciler_log" "$repo_root/scripts/check-installed-state.sh"
 mapfile -t remote_call <"$remote_reconciler_log"
-[[ ${remote_call[0]} == "--check-only --desired-ref $ref_one" && ${remote_call[1]} == "$install_state" ]] || fail 'remote drift check did not delegate the exact installed state to authenticated reconciliation'
+[[ ${remote_call[0]} == "--check-only --installed-ref" && ${remote_call[1]} == "$install_state" ]] || fail 'remote drift check did not delegate the exact installed state to authenticated reconciliation'
 expect_success "$installer" --install "${base_args[@]}" --ref "$ref_one" >/dev/null
 
 export FAKE_DISABLED_TIMER=ci-fleet-cleanup.timer
diff --git a/scripts/test_remote_reconcile.py b/scripts/test_remote_reconcile.py
index 2c4851c3..c2308297 100644
--- a/scripts/test_remote_reconcile.py
+++ b/scripts/test_remote_reconcile.py
@@ -197,20 +197,24 @@ def test_help_exits_0(self):
         self.assertEqual(result.returncode, 0)
         self.assertIn("usage", result.stdout + result.stderr)
 
-    def test_desired_ref_is_full_sha_and_check_only(self):
-        invalid = subprocess.run(
-            [str(RECONCILE_SCRIPT), "--check-only", "--desired-ref", "main"],
-            capture_output=True, text=True, env=self.env,
-        )
+    def test_installed_ref_is_check_only(self):
         mutating = subprocess.run(
-            [str(RECONCILE_SCRIPT), "--desired-ref", "a" * 40],
+            [str(RECONCILE_SCRIPT), "--installed-ref"],
             capture_output=True, text=True, env=self.env,
         )
-        self.assertEqual(invalid.returncode, 2)
-        self.assertIn("full lowercase commit SHA", invalid.stderr)
         self.assertEqual(mutating.returncode, 2)
         self.assertIn("requires --check-only", mutating.stderr)
 
+    def test_installed_ref_rejects_symbolic_state_before_fetch(self):
+        self._write_state("RandomDevelopment/rd-delivery-config", "HEAD", "rd-ci-fleet-01")
+        result = subprocess.run(
+            [str(RECONCILE_SCRIPT), "--check-only", "--installed-ref"],
+            capture_output=True, text=True, env=self.env,
+        )
+        self.assertEqual(result.returncode, 2)
+        self.assertIn("full lowercase commit SHA", result.stderr)
+        self.assertNotIn("GENERATING_TOKEN", result.stdout)
+
     def test_reconcile_state_saved_on_failure(self):
         """State file is saved even when reconciliation fails."""
         result = subprocess.run(
@@ -263,6 +267,9 @@ def test_remote_installer_calls_keep_identity_and_lock(self):
         reconcile = RECONCILE_SCRIPT.read_text()
         installer = INSTALLER.read_text()
         self.assertNotIn("release_lock", reconcile)
+        self.assertIn('flock -w "$lock_wait_seconds" 9', reconcile)
+        self.assertLess(reconcile.index('flock -w "$lock_wait_seconds" 9'), reconcile.index("fetch_ref=HEAD"))
+        self.assertIn('fetch_ref=$installed_config_ref', reconcile)
         self.assertEqual(reconcile.count("CI_FLEET_INSTALLER_LOCK_FD=9"), 3)
         self.assertEqual(reconcile.count("--config-identity"), 3)
         self.assertIn("--config-identity)", installer)