Thermostat displays E11 and cannot complete firmware update via the Baxi app.

Safety note: Do not remove power during an active firmware update unless instructed by Baxi support.

Steps to resolve:

• 1. Ensure stable Wi‑Fi: Move your router closer or improve signal strength. Avoid starting updates during network congestion.
• 2. Check power/battery: For battery-powered models, fit fresh batteries before retrying the update. For mains-powered, ensure no planned power cuts.
• 3. Retry update: Use the Baxi app to restart the firmware update. Wait until the process fully completes.
• 4. Factory reset if stuck: If the thermostat is stuck on E11, perform a factory reset as per the manual, then reconnect it to the app and attempt the update again.

When to call a professional: If the thermostat will not boot normally after an update attempt, it may be bricked and require replacement under warranty.