Help flashing Tasmota on Sonoff S31

I have several Sonoff S31 switches. I’m trying to flash the Tasmota firmware on them. I’ve followed information found on the web, but in spite of using several different USB-serial adapters I am never able to flash the new firmware. I’ve tried using PlatformIO as well as esptool. The flashing tool simply fails to connect with the S31. I hold the button down, plug in the adapter to the computer, continue to hold the button for a second or two, then release it and try to flash.

Can any kind soul who has flashed a S31 before lend me a hand? Thanks!

the connections are VCC, RX, TX, N/C, N/C, GND (Notice the two unused pads labeled TX & RX. They don’t appear to be connected.)
S31 TX ------>RX USB-serial adapters
S31 RX ------>TX USB-serial adapters

Yes, that’s how I have it connected. It is acting like the S31 is not going into flash mode. Are there any LEDs which should be on when it is in this mode?


You should ask a dedicated forum:!forum/sonoffusers

Thank you. I will post there.