4-Zone Wall Controller Firmware v2026-05-17: Relay Inversion, OTA Updates, and Version Display

This firmware update is for the TekOnline 4-Zone Wall Controller.

Current firmware version:

2026.05.17-v2-hold-dimmer-unique-spill-invert

What changed

This release keeps the existing hold-to-dim and spill-zone behaviour, and adds three support-focused improvements:

per-zone relay inversion switches
a TekOnline firmware version visible in Home Assistant
clearer support for OTA updates from the ESPHome Dashboard

Per-zone relay inversion

Some HVAC zone interfaces behave as active-high outputs. Others behave as active-low outputs.

If a zone behaves backwards, for example off in Home Assistant turns the HVAC output on, use the new inversion switch for that zone.

In Home Assistant, look for:

Zone 1 Relay Inverted
Zone 2 Relay Inverted
Zone 3 Relay Inverted
Zone 4 Relay Inverted

Turn on the inversion switch only for the zone that behaves backwards.

If all zones behave backwards, turn on all four inversion switches.

Firmware version in Home Assistant

The controller now exposes a diagnostic entity called:

4 Zone Wall Controller Firmware Version

This makes support easier because you can confirm exactly which TekOnline firmware build is installed without opening the ESPHome YAML.

The controller also exposes:

4 Zone Wall Controller ESPHome Version

OTA updates

If the controller is already online and already running ESPHome firmware, you can usually update it over the network:

Add the YAML to your ESPHome Dashboard.
Click Install.
Choose Wirelessly.

If ESPHome cannot find the device by hostname, find the controller's IP address in Home Assistant or your router and temporarily add use_address to your local copy of the YAML:

wifi:
  use_address: 192.168.1.123

Replace 192.168.1.123 with your controller's actual IP address.

Do not add a private IP address to the public/shared YAML file.

If OTA is not available

OTA only works if ESPHome firmware is already running on the controller and the controller is reachable on your network.

If the ESP32 flash has been wiped, or if the current firmware does not support OTA, use USB flashing first.

After a successful USB flash with ESPHome firmware, future updates can usually be done wirelessly.

Download

Use the current public firmware file:

tekonline-4zone-wall-controller-v2026-05-17.yml

If WordPress supplies the file as .txt, download it and rename it from:

tekonline-4zone-wall-controller-v2026-05-17.txt

to:

tekonline-4zone-wall-controller-v2026-05-17.yml

Then add the .yml file to your ESPHome Dashboard and install it.

Need help?

Contact TekOnline and include:

whether the controller is currently online
the controller IP address, if known
your ESPHome version
the firmware version shown in Home Assistant, if available
whether any zones appear inverted