Hello I would like to flash Sonoff Touch with BTE13-009 USB to TTL. This converter is switchable 5V to 3,3V. But there is problem that if you switch to 3,3V voltage on VCC is changed but logic level (TX,RX) stays at 5V. Is this problem and will board be burned?
As described here http://www.ba0sh1.com/blog/2016/08/03/is-esp8266-io-really-5v-tolerant/
ESP is 5V tolerant. So will be Sonoff OK with 5V on logic level?
Did you manage to get an answer to your question? I have the same situation.