Moderator: igrr
However, I have found a method which works for me with Windows10 and I hope will work for others too. Firstly I compile a sketch in the IDE and then export it as a .bin file. Close the IDE and then run esp8266_flasher.exe (see link below), select the com port and previously saved bin file and click the 'Download' button in flasher window. Currently I have 100% success with flashing the ESP-12 using this method.
It seems to me that something is amiss with Arduino-ESP flashing, as so many users experience the same upload failures but esp_flasher works.
esp8266_flasher.exe can be downloaded from: https://github.com/Stadslab/ESP8266_exa ... te%20Ready
I trust that others will try this method where upload failures are experienced and report back with their findings.
Edit: As a follow up, I have since discovered that esp8266_flasher.exe runs ok with linux/wine with a symlink to the com port but does not successfully upload to the esp8266. It connects ok but stalls at about 45% upload, so it seems that I will have to use windows for now.