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E43 — WS_CONNECTION_LOST_DURING_OTA

The WebSocket connection was lost while an OTA firmware update was in progress.

What happens​

The error is logged, the error log is saved to NVS, the display shows "Connection lost / during update", and the device reboots after 5 seconds. The bootloader will attempt to boot the last valid firmware slot (the update did not complete).

Possible causes​

  • Wi-Fi signal dropped during the update.
  • The FKMTime server restarted or lost connectivity mid-transfer.
  • Network congestion caused the WebSocket to time out.

How to fix​

  1. Wait for the device to reboot — It will come back up on the previous firmware automatically. Confirm normal operation before attempting the update again.
  2. Improve Wi-Fi conditions — Move the device closer to the access point and retry the update when the connection is stable.
  3. Retry the OTA update — Trigger it again from the FKMTime web interface once the device is back online.