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Shelly Multicolor Bulb E27 Gen3

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State: confirmed Generation: 3 Chip: ESP32-C3

🧰 Before you start · ⚙️ Config · ⚡ Flash it · 👀 What to expect · ↩️ Way back

The LEDs sit behind a KP18068 5-channel driver on SDA GPIO4 / SCL GPIO5. ESPHome has no official driver for it, so the example config uses the external component oxynatOr/esphome-kp18058.

Fact Value
Profile RGBCCTBulbG3
Flash 8 MB
Official package 2.0.1
Partition table 0x10000
App slot size 0x280000

Note

Confirmed: the whole chain ran on a real device: send with --esphome-factory ran through, ESPHome runs and the light was tested on the bulb (owner, 2026-10-11): channel order and the single warm white LED confirmed. Colour accuracy, the lowest dimming steps and the driver currents are not measured. The colour temperature light of the example config (rgbw_ct_table, stock table) was flashed afterwards and runs (owner, 2026-10-16); its colours were not compared with the stock firmware.

Before you start

Check first:

  • the device runs Shelly's own firmware, not ESPHome yet
  • you know its IP address (--ip), or this PC is on the device's own access point (default 192.168.33.1)
  • the device can reach this PC: same network, port 8000 (--port) not blocked
  • your ESPHome config uses the partition table below and is compiled
  • a UART adapter is at hand as your way back (Recovery over UART)

ESPHome config

Important

build refuses a config without Shelly's partition table. Copy partitions/RGBCCTBulbG3-stock.csv from this repository next to your YAML and keep CONFIG_PARTITION_TABLE_OFFSET: "0x10000".

esp32:
  variant: ESP32C3
  board: esp32-c3-devkitm-1
  flash_size: 8MB
  partitions: RGBCCTBulbG3-stock.csv        # copy from partitions/ in this repository
  framework:
    type: esp-idf
    sdkconfig_options:
      CONFIG_PARTITION_TABLE_OFFSET: "0x10000"
    advanced:
      enable_ota_rollback: false

ota:
  - platform: esphome
    allow_partition_access: true

The full example config (RGB + colour temperature light with the stock firmware's table and white balance, current codes as the Shelly firmware sends them) and the optional light packages (daylight, scenes, wake-up alarm, night light, over-temperature protection, dim range) are kept in oxynatOr/esphome-configs, not in this repository. The config pulls the driver component esphome-kp18058 through external_components.

Channel order, read from the stock firmware and tested on the bulb (owner, 2026-10-11): OUT1 = blue, OUT2 = red, OUT3 = green, OUT4 = the one warm white LED; OUT5 shows nothing on its own. OUT4 and OUT5 get the same value (one white level). The stock firmware makes colour temperatures from 2700 to 6500 K by mixing red, green and blue into that white (a 9-point table); the example config does the same with the light platform rgbw_ct_table (see its README).

Flash it

  1. Install the requirements (once):
pip install -r requirements.txt
  1. Fetch the official package:
python ota.py fetch RGBCCTBulbG3 --insecure
  1. Build: put your app into it; the ZIP goes to out/:
python ota.py build RGBCCTBulbG3 app.ota.bin --esphome-factory app.factory.bin --esphome-yaml shelly-rgbcct-bulb-g3.yaml
  1. Check the device first. Nothing is sent:
python ota.py send RGBCCTBulbG3 out/RGBCCTBulbG3-app-<date>.zip --ip <device IP> --dry-run
  1. Flash it (the log goes to a file with --log-file):
python ota.py send RGBCCTBulbG3 out/RGBCCTBulbG3-app-<date>.zip --ip <device IP> --log-file

app.ota.bin and app.factory.bin are the two files ESPHome compiles. --dry-run only checks the device and, for this package, reads the update target slot. Command reference: Commands.

What to expect

send shows these lines at the default log level, in this order:

# Log line Meaning
1 Update target slot: 0 ... The slot check of send. Anything else: run python ota.py restore RGBCCTBulbG3 first
2 Device: The bootloader will be replaced ... (raw log: Boot: cur ... min ... update? 1) The installer will write ESPHome's bootloader. WARNING: ESPHome's bootloader was NOT written (update? 0) means it will not: build again with a higher --boot-min-version (why)
3 The progress (Update: ... %, one line that updates in place) up to 100 %, then Done: update installed, the device confirmed it The device restarts into ESPHome

Notes for this device

  • Installed loader: on the first install the bulb ran Shelly OS loader 1.0.2 (visible on UART), and the default min_version 1.0.3 was enough. After a return to stock the bulb runs loader 1.0.3, so the profile sets boot_min_version: 1.0.9; with it the ESPHome bootloader was written (hardware-confirmed 2026-10-11).
  • Dark bulb? The driver component bit-bangs the two pins and expects an ACK for every byte. Try ignore_ack: true first; the other suspects are the address byte 0xE1 (Shelly's I2C hardware sends 0xE0) and the internal pull-ups at a faster clock than Shelly's 100 kHz. Details: Notes & troubleshooting of the driver component.

Way back

python ota.py restore RGBCCTBulbG3 sends the official firmware back while Shelly firmware still runs.

Warning

  • Wipes Wi-Fi and settings. ESPHome opens its own access point or joins the Wi-Fi from your config; if nothing comes up, power-cycle the device (help).
  • No way back over the network once ESPHome's bootloader runs: restore gets no answer, only UART brings Shelly OS back (Recovery over UART). Take a flash backup first if you can.
  • Flashed it? Tell us, also when it worked: open a device report.

Bootloader and slots · Troubleshooting · Recovery over UART