title: ESP8266 error: espcomm_upload_mem failed while uploading sketch
body: <p>First of all, I would like to apologize for posting this error once again to this community. However, I have been studying articles for last many days to resolve this error. Unfortunately, I did not get any solution which could resolve my problem.</p>
  
  <p>Below is the error which I get when uploading a sketch (even the example sketch):</p>
  
  <p><strong>warning: espcomm_sync failed
  error: espcomm_open failed
  error: espcomm_upload_mem failed
  error: espcomm_upload_mem failed</strong></p>
  
  <p>Here are the connections:<br>
  Vcc - 3.3V<br>
  RST - 3.3v<br>
  CH_PD - 3.3v<br>
  Tx - Rx<br>
  Rx - Tx<br>
  GPIO0 - GND<br>
  GND - GND</p>
  
  <p>I tried various combinations like Tx to Tx, Rx to Rx, pulling off GPIO0. Pulling off reset and ch_pd. Supplying external power source, supplying power directly from Arduino using 3.3V. Supplying power from Arduino 5V using an LD33V regulator. I have even tried uploading the code using USB to TTL. But every time I get exactly the same error.</p>