Esp8266 erase flash.

process.env
={
  "VERSION": "1v95",
  "BUILD_DATE": "Dec 15 2017",
  "BUILD_TIME": "17:10:27",
  "GIT_COMMIT": "7dbffcf5da09570bd95714b2386a12ab25ab1d50",
  "BOARD": "ESP8266_4MB",
  "CHIP": "ESP8266",
  "CHIP_FAMILY": "ESP8266",
  "FLASH": 0, "RAM": 81920,
  "SERIAL": "6001943c-9f1e",
  "CONSOLE": "Serial1",
  "EXPORTS": { "jsvLock": 1075854228, "jsvLockAgainSafe": 1075854316, "jsvUnLock": 1075854940, "jsvSkipName": 1075864796,
    "jsvMathsOp": 1075871204, "jsvMathsOpSkipNames": 1075872992, "jsvNewFromFloat": 1075862156, "jsvNewFromInteger": 1075862040, "jsvNewFromString": 1075861816,
    "jsvNewFromBool": 1075862124, "jsvGetFloat": 1075868928, "jsvGetInteger": 1075864092, "jsvGetBool": 1075869304, "jspeiFindInScopes": 1075887224,
    "jspReplaceWith": 1075886908, "jspeFunctionCall": 1075898260, "jspGetNamedVariable": 1075889136, "jspGetNamedField": 1075889580, "jspGetVarNamedField": 1075889712,
    "jsvNewWithFlags": 1075861420 }
 }
>r