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Shelly 2PM Gen3

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State: confirmed Generation: 3 Chip: ESP32-C3

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

Gen3 / ESP32-C3.

Fact Value
Profile S2PMG3
Flash 8 MB
Official package 2.1.0
Partition table 0x10000
App slot size 0x2c0000
ESPHome device page Shelly 2 PM Gen3

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/S2PMG3-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: S2PMG3-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

Tip

The ESPHome device page has a config to start from. Replace its esp32: block with the one above, or build refuses it.

Flash it

  1. Install the requirements (once):
pip install -r requirements.txt
  1. Fetch the official package:
python ota.py fetch S2PMG3 --insecure
  1. Build: put your app into it; the ZIP goes to out/:
python ota.py build S2PMG3 app.ota.bin --esphome-factory app.factory.bin --esphome-yaml app.yaml
  1. Check the device first. Nothing is sent:
python ota.py send S2PMG3 out/S2PMG3-app-<date>.zip --ip <device IP> --dry-run
  1. Flash it and watch the log:
python ota.py send S2PMG3 out/S2PMG3-app-<date>.zip --ip <device IP> --watch 120

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

In the --watch log look for these lines, in this order:

# Log line Meaning
1 Update target slot: 0 ... The slot check of send. Anything else: run python ota.py restore S2PMG3 first
2 Boot: cur ... min ... update? 1 The installer will write ESPHome's bootloader. update? 0 means it will not: build again with a higher --boot-min-version (why)
3 ota_progress up to 95 %, then ota_success The device restarts into ESPHome

Notes for this device

First report (#92, thanks to majoto85): flashed over OTA from Shelly 1.4.99 (running from slot 1) with --esphome-factory. The installer wrote ESPHome's bootloader (loader 010001ff, minimum 010009ff) and the device booted straight into ESPHome without a power cycle, joined Wi-Fi, and a later regular ESPHome OTA took effect. Relays and the meter were not part of the report.

  • Two more units (thanks to WulffTech): S3SW-002P16EU, from Shelly 2.0.1 to ESPHome 2026.9.0 over OTA without UART, built with their own tooling instead of ota.py. Both ran stable across reboots, the relays stayed off after them, and a later ESPHome OTA worked. The meter was not reported.
  • Slot: the first --dry-run could not read the target slot (8 s timeout); a second one right after showed slot 0.
  • The installer logs refused eFuse writes (FW signatures: want 07, got 00). The update still finished and the device confirmed it.

The profile sets boot_min_version: "1.0.9": devices of this family run Shelly's loader 1.0.3, which would otherwise skip ESPHome's bootloader (update? 0).

Way back

python ota.py restore S2PMG3 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