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ESPHome firmware for Ultima and xU Series

SLZB ESPHome Firmware Flashing Guide for SLZB-Ultima, MRxU and 06xU

  1. Open SLZB-ESPHome repository: https://github.com/smlight-tech/slzb-esphome

  2. Download the firmware file that matches your device:

    • SLZB-Ultima → ultima-r1-04xx

    • SLZB-MRxU series → MRxU-r1-73xx (only for models with U)

    • SLZB-06xU series → 06xU-r1-73xx (only for models with U)
      Make sure you select the correct file for your product.

  3. Connect your SLZB device to your computer using a USB cable.

  4. Download and open the flashing tool (easiest one is here: https://github.com/Jason2866/ESP_Flasher/releases/tag/v3.2.0).

  5. In the flasher tool, select the firmware file you downloaded and start flashing.

  6. If flashing does not start, unplug the device, press and hold the button on the device (on SLZB-UltimaUltima, this is the first button from the left), keep it pressed, plug the USB cable back in, and try flashing again.

  7. Wait until flashing finishes.

  8. Open Home Assistant. Your device should appear automatically. If it does not, add it manually in the ESPHome integration using the device’s IP address.

Ports for Z2M/ZHA/OTBR/ZWavejSUI configs:

Ultima:

      • EFR32 SoC: 6638
      • CC26 SoC: 7638
      • ZWave: 8638

SLZB-MRxU

      • EFR32/ZWave SoC: 6638
      • CC26 SoC: 7638

SLZB-06xU

      • EFR32/CC26 SoC: 6638

Remarks:

  • The web server is turned OFF by default because of this: https://esphome.io/components/bluetooth_proxy/#memory-issues
  • Bluetooth proxy is turned on by default in the existing builds. If you want to build your own firmware, please use YAML and compile your firmware.

Moving back from ESPHome:

To flash the SLZB-OS to the device, please use the official flasher https://smlight.tech/flasher/#SLZB-06U-MRxU.

If flashing does not start, unplug the device, press and hold the button on the device (on SLZB-Ultima, this is the first button from the left), keep it pressed, plug the USB cable back in, and try flashing again. This is because your USB port could be in Host mode, and the button forces ESP to be in Flash mode.

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