title: ESP8622 with NodeMCU firmware starts blinking after flashing new version of firmware (old builds are working)
body: <p>Yesterday i tried to generate new firmware bin from nodemcu-build.com and after flashing with esptool.py, my esp started blinking (blue diode on esp chip) and sending out (trough USB converter) garbage data. I tried to generate build with combination of modules, tried to flash them (binary and float) and it always start blinking and sending out garbage. Than my co-worker tried his older build and everything worked perfectly, than he send me his older build and after flashing everything works also perfectly. So there is no problem with flashing tool or system (tested on both mac and linux) and no problem with old builds. Any new build is failing for us.</p>
  
  <p><strong>My flashing command:</strong> </p>
  
  <blockquote>
    <p>esptool.py -p /dev/cu.wchusbserialfa130 write_flash 0x0
    nodemcu-master-13-modules-2016-04-09-12-28-55-float.bin --verify</p>
  </blockquote>
  
  <p>Anybody idea where is possible problem or what we doing wrong?</p>