use esp8266 dev board as a serial programmer

[itamar93]

Hi,

I'm trying to program a Sonoff Pow Elite device using esptool and, due to lack of a usb to ttl adapter, a esp8266 development board which acts as the serial programmer.
I connected the esp8266 dev board to my pc, and the 3.3v & gnd pins from the dev board to the sonoff vcc & gnd pins and was able to ramp up the sonoff device by seeing a blue led blinking.
Moreover, I connected the tx & rx pins from the dev board to the rx & tx pins on the sonoff board. I insert the sonoff into bootloader mode and tried to read its flash id using esptool but it didn't success. I measured the output voltage from the tx pin and it shows ~2.7v and I concern that this is the issue.
Someone succeeded communicating a sonoff device using the same setup?

Thanks

[rin67630]

Use a Witty ESP8266 board
It has the programing part and the ESP on two separate boards, so you can use the programming circuit without having the ESP interfering with the reset sequence.