• https://github.com/arendst/Sonoff-Tasmota/wiki/H801

• https://github.com/arendst/Sonoff-Tasmota/wiki/Esptool

dpavlin@nuc:/nuc/esptool$ wget https://github.com/arendst/Sonoff-Tasmota/releases/download/v6.2.1/sonoff-sensors.bin

pi@rpi2 /nuc/esptool $ ./esptool.py --port /dev/ttyUSB2 write_flash -fs 1MB -fm dout 0x0 ./sonoff-sensors.bin 
esptool.py v2.3-dev
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Compressed 506336 bytes to 345467...
Wrote 506336 bytes (345467 compressed) at 0x00000000 in 31.6 seconds (effective 128.3 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...