Sonoff Dual R2 2CH Wifi Switch

Sonoff Dual R2 is the replacement for Sonoff Dual. Compared to the dual, the main improvements for R2 are:

* Since the removal of the second microcontroller, the two relays are now directly controlled by an ESP8285
* The button is now directly connected to the ESP8285
* Header connector now supports Tasmota

Sonoff Dual R2 series flashing
As always, you must access the serial interface. VCC, RX, TX and GND are available at the bottom left of the card in the image below.

Programming the Sonoff Dual R2 is very easy, even if the integrated button is not connected to GPIO0. As with all ESP8266 / ESP8285 modules, GPIO0 must be connected to GND to put the chip into programming mode. You must connect GPIO0 and GND when powering on.

Fortunately, GND and GPIO0 (like KEY 0) are available in the second header. A simple jumper between GND and BUTTON 0 when turned on is sufficient.

You can find a video about flashing the Sonoff Dual R2 with Tasmota here.

Use external switches
Relays can be controlled by external buttons or switches connected to the header at specified positions. KEY 0 (for GPIO0) connected to the GND 1 controller relay and KEY 1 (for GPIO9) to the GND 2 controller relay.

NOTE Make sure that you are not using a switch that keeps the connection between GND and KEY 0 active during power restore, as the device starts in programming mode.