minor fixess

README.md

@@ -81,6 +81,12 @@ BUTTONTASK_CONFIG=../config/config.json python3 app.py
 ```
 Open `http://<device-ip>:8080`. Login: `admin` + the password from `settings.password`.
 
+**Web port (`settings.webPort`):** use **1024 or higher** (default `8080`). On Linux,
+ports **1–1023** are *privileged*: the web service runs as the unprivileged
+`buttontask` user and cannot bind to them unless the systemd unit grants
+`CAP_NET_BIND_SERVICE` (see `webconfig/buttontask-web.service`). Setting e.g. port
+80 without that capability causes `Permission denied` and a restart loop.
+
 ## Deployment with systemd (versioned layout)
 
 The device uses an A/B-style versioned layout so OTA updates can roll back:
@@ -278,7 +284,7 @@ live and is also readable in the app's **Обновление** page.
     "password": "admin",     // shared with web auth
     "kioskMode": false,
     "iconsDir": "/opt/buttontask/icons",   // dir for user icons & background images
-    "webPort": 8080
+    "webPort": 8080          // use >= 1024 (1–1023 need root / CAP_NET_BIND_SERVICE)
   },
   "buttons": [
     {