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Shelly Duo Bulb Gen3

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State: partly checked Generation: 3 Chip: ESP32-C3 Pins: not confirmed

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

The owner reports the same main board as the Multicolor Bulb with a different lamp module. The Duo's stock firmware has no I2C code: it drives the LEDs with PWM (LEDC), so the LED driver config of the Multicolor Bulb does not apply. The pins (below) come from the analysis of a flash dump of the stock firmware, not from a test on the lit lamp.

Fact Value
Profile DuoBulbG3
Flash 8 MB
Official package 2.0.1
Partition table 0x10000
App slot size 0x280000

Note

Partly checked: the owner flashed the package from this tool over OTA and the bulb runs ESPHome (before that an ESPHome config was flashed over UART). The GPIOs are not confirmed on the hardware (they were not checked with the LEDs); they come from the stock firmware, see Pins. The log of the OTA run is not recorded here.

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

Also:

  • A UART adapter is at hand as your way back; the bulb has a non-isolated mains supply, see the warning below (Recovery over UART).

ESPHome config

Important

build refuses a config without Shelly's partition table. Copy partitions/DuoBulbG3-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: DuoBulbG3-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

Pins

Function Pin
Warm white (LEDC PWM) GPIO4 (module pad MTMS)
Cold white (LEDC PWM) GPIO5 (module pad MTDI)
BOOT (download mode, low-active) GPIO9

Source: the stock firmware dump. Like the Gen1 bulbs, the Duo drives its two white channels directly with PWM (two LEDC channels, warm on GPIO4, cold on GPIO5). The owner's ESPHome config (flashed over UART, cwww light, constant_brightness: true) uses the same pins and runs, but the pins were not confirmed on the hardware. No energy meter chip is known.

Warning

The bulb has a non-isolated mains supply. Never connect a serial adapter while it is in the socket; take it out and power it from the adapter's 3.3 V.

Flash it

  1. Install the requirements (once):
pip install -r requirements.txt
  1. Fetch the official package:
python ota.py fetch DuoBulbG3 --insecure
  1. Build: put your app into it; the ZIP goes to out/:
python ota.py build DuoBulbG3 app.ota.bin --esphome-factory app.factory.bin --esphome-yaml app.yaml
  1. Check the device first. Nothing is sent:
python ota.py send DuoBulbG3 out/DuoBulbG3-app-<date>.zip --ip <device IP> --dry-run
  1. Flash it (the log goes to a file with --log-file):
python ota.py send DuoBulbG3 out/DuoBulbG3-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 DuoBulbG3 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

The OTA chain is the same as on the Multicolor Bulb, and the owner has run it with this tool. The profile sets boot_min_version: 1.0.9 because the Multicolor Bulb (same main board) runs loader 1.0.3 after a return to stock, which the default 1.0.3 would skip. Please report the file written by --log-file, especially the line Boot: cur ... min ... update?.

Way back

python ota.py restore DuoBulbG3 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