I just wanted to share that I was getting errors like espcomm_sync ailed and espcomm_upload_mem failed. After trying everyone’s tips, numerous settings, different arduinos, and testing connections with a multimeter, it wasn’t until I used some rubbing alcohol to clean up the flux on the board around the ESP8266 Module that I was able to get past those errors. My only guess as to why that worked is the flux must have been on there heavily enough enough to cause a little bit of conductivity or resistance between a couple of the contacts.
