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Common features

The following features are available for all battery operated Shelly BLU devices. For device specific functions, refer to the corresponding device's page.

Support Over The Air firmware update (OTA)

Keeping up to date with the latest firmware features and bug fixes is important. Fortunately, the Shelly BLU devices are relatively simple and do not require frequent updates if any at all.

Firmware update is acomplished with the help of Shelly BLE Debug mobile application available in Google play and Apple App store or from Shelly Smart Control App available at Google play and Apple App store, if the device is registered in the user's account. The firmware for OTA is encrypted with specific key for the corresponding device.

Important: Failure to finish OTA update will leave the device in bootloader mode. The device will switch itself to sleep mode after 40 seconds. Pressing the button will awake it for another 40 seconds. The OTA process can be repeated from bootloader mode.


The connection to the device and the data payload of the BTHome compatible packet support ecryption. Ecryption can be easily done using the Shelly mobile applications. For detailed description see: Encryption


The devices can be connected, controlled and modified only from a paired peer. Pairing requires entering a special pairing mode by holding the device's button for more than 10 seconds. Pairing mode is indicated by blue flashing LED on devices with LEDs. If the device is encrypted, the connection to it will require entering the PIN code used for encryption. Pairing mode will be terminated after 1 minute idle, or by connecting to the device. The maximum number of paried devices is 4. Further pairing is possible, but will discard paring keys from the least used peer device.

Beacon mode

With beacon mode activated, the device will periodically emit data packets with its battery level and status. This mode can be used for presence detection, or for keep-alive, or for collecting sensor data from the device. Some devices have beacon mode as their basic functionality and therefore they do not have a corresponding setting for enable/disable beacon mode.

Factory reset

The factory reset function erases all pairing keys from the device and restores the default settings. It can be accomplished either by writting to the factory reset characteristic or by removing the battery, then placing it back and, finally, holding the button of the device for more than 30 seconds.

Common GATT Services and characteristics

Factory resetb0a7e40f-2b87-49db-801c-eb3686a24bdbbyte1Write bonded, write without response bondedWrite 1 to restore factory settings
Passkey0ffb7104-860c-49ae-8989-1f946d5f6c03byte4Write bonded, write without response bondedUser defined passkey for bonding and encryption (0-999999). Little endian encoded
Beacon mode enabledcb9e957e-952d-4761-a7e1-4416494a5bfabyte1Read, Write bonded, write without response bondedEnables periodic beacons
Reconnection Address00002a03-0000-1000-8000-00805f9b34fbbyte6ReadDevice MAC address in OTA mode (Bootloader active)
Encryption keyeb0fb41b-af4b-4724-a6f9-974f55aba81abyte16Read bondedAES CCM encryption key (based on the current passkey)
Unix timed56a3410-115e-41d1-945b-3a7f189966a1byte4Read, Write bonded, write without response bondedDevice unix time
Sample BTHome datad52246df-98ac-4d21-be1b-70d5f66a5ddb--ReadUnencrypted BTHome data from the device

Common BTHome data objects for FW and device identification

The packets is emited at device power on / restart and every 6 hours.

idnamedata typescale factordescription
0x00packet iduint81revolving counter
0x01batteryuint81battery level in percent (0-100)
0xF0device type iduint161device internal identification number
0xF1firmware versionuint321firmware version in format major.minor.patch.rc