What are the usable extra GPIOs on a Sonoff POW R2?

[RendyIrawan]

I noticed that in a Sonoff POW R2, there are the pins GPIO4 and GPIO5 on the board next to the TX, RX, GND, and VCC PIN. Does that mean that if I flash ESPHome to it, I would be able to use those pins to use as I²C’s SDA & SCL pin or to hook up an additional sensor like a Dallas DS18B20 or a flow sensor to it?

Another quick question: Since the CSE7766 Power Sensor on the POW R2 only requires the RX pin, does that mean the TX (GPIO 1) pin is also free for me to use as an output pin?

Here’s a photo of the internal pins I found from a quick Google search:

And here’s the pinout reference for ES8266s from randomnerdtutorials.com

Or maybe somebody here has successfully utilized those pins on a ESPHome or even Tasmota flashed Sonoff POW R2? Would love to hear about it. Thanks fellas!

[Hellis81]

I didn’t look at it too closely but here is some information:
Sonoff Pow R2 Power Monitoring Switch Module Configuration for Tasmota (blakadder.com)

[tom_l]

Do not connect any devices to the GPIOs. They are not isolated from mains power.

[tom_l]

Do not advise people to use the POW2 GPIOs.