Replacing the vendor firmware of the Hitachi AirHome 400 (and possibly other models) WiFi module with a custom version based on ESPHome.
Since recent versions of Hitachi AC are shipped with integrated WiFi connectivity, it is not necessary to add custom hardware. Instead, it is possible to flash a custom firmware onto the WiFi module.
Follow the instructions to flash your custom firmware.
Once done, next updates can be done OTA using Esphome. No special instructions are required then.
Libretiny documentation states: "Because the UART uploading code is programmed in the ROM of the chip, it can't be software-bricked, even if you damage the bootloader". This means that it should be safe to flash custom firmware. However, you remain responsible if any problems occur.
Use hitachi_altwifi.yaml as a package in your main esphome yaml file (set the climate name using the custom var ac_name):
packages:
hitachi_ac: !include
file: hitachi_altwifi.yaml
vars:
ac_name: ${ac_name}
This list references tested models only. If another model is compatible, please report it to help extend this list.
- RAK-DJ18RH
- RAK-DJ50RH
This project initially relied on custom firmware from esphome-hlink-ac. However, firmware decompilation as well as UART sniffing revealed a new, undocumented protocol, which, for convenience, will be referred to as hlink2.
A new firmware targeting hlink2 is now available. It supports additional features such as 0.5 °C temperature increments. The firmware has been successfully tested on at least two AC units but should still be considered experimental at this stage
Use the provided model configuration file to build your firmware.
Initial custom firmware provided by esphome-hlink-ac for legacy binary HLINK protocol.
This repository is not affiliated with Hitachi in any way.
This repository and its content are licensed under the EUPL-1.2-or-later.
Check https://joinup.ec.europa.eu/collection/eupl/eupl-text-eupl-12