diff --git a/modules/app_device_config.py b/modules/app_device_config.py
index 5b9cad5..fbf5ba2 100644
--- a/modules/app_device_config.py
+++ b/modules/app_device_config.py
@@ -36,10 +36,14 @@ def update_device_config(body, errors):
         # Allow toggling sync_enabled off
         if "sync_enabled" in body and not body["sync_enabled"]:
             _set_sync_enabled(False)
-            # Toggling off is always allowed — don't return error even if
-            # other locked fields are in the body (the JS always sends them).
+            # Toggling off is always allowed — don't error on locked fields
+            # (the JS always sends them alongside the toggle).
             return errors
-        # User cannot edit locked fields while syncing from server.
+        # Sync is staying enabled — locked fields are ignored silently.
+        # The JS always sends them; rejecting would break the save flow.
+        if "sync_enabled" in body and body["sync_enabled"]:
+            return errors
+        # User tried to edit locked fields without the sync toggle — reject.
         if any(k in body for k in ["owner_name", "car_model", "avatar_path"]):
             errors["error"] = "Cannot edit device config while server sync is enabled. Server is source of truth."
         return errors
diff --git a/static/js/settings.js b/static/js/settings.js
index ad0cc76..a756fa4 100644
--- a/static/js/settings.js
+++ b/static/js/settings.js
@@ -459,20 +459,18 @@ form.addEventListener('submit', async event => {
         }
         populateRemoteConfig(remoteConfigResult);
 
-        // Save device config (skip if sync is enabled — server is source of truth)
-        if (!fields.deviceSyncEnabled.checked) {
-            const deviceConfigResponse = await fetch('/api/device-config', {
-                method: 'POST',
-                headers: {'Content-Type': 'application/json'},
-                body: JSON.stringify(deviceConfigPayload()),
-            });
-            const deviceConfigResult = await deviceConfigResponse.json();
-            if (!deviceConfigResponse.ok) {
-                applyErrors(deviceConfigResult.fields || {});
-                throw new Error(deviceConfigResult.error || `HTTP ${deviceConfigResponse.status}`);
-            }
-            populateDeviceConfig(deviceConfigResult);
+        // Save device config (always send — backend validates locked fields when sync is on)
+        const deviceConfigResponse = await fetch('/api/device-config', {
+            method: 'POST',
+            headers: {'Content-Type': 'application/json'},
+            body: JSON.stringify(deviceConfigPayload()),
+        });
+        const deviceConfigResult = await deviceConfigResponse.json();
+        if (!deviceConfigResponse.ok) {
+            applyErrors(deviceConfigResult.fields || {});
+            throw new Error(deviceConfigResult.error || `HTTP ${deviceConfigResponse.status}`);
         }
+        populateDeviceConfig(deviceConfigResult);
         
         showMessage('Settings saved.', 'success');
     } catch (error) {