I had ESP flasher work 1 time for me on sdk 140, before that had few problems, but
after that I could not get it to work, until I went with the ESP DOWNLOAD FLASHER
You can try it , may work fine for you, just remember there is a good alternate.
after / if it boots the normal baud is 9600,, I have connected 74880 there bouts,
have never connected 115200 after burn/boot....
I have posted pool/spa monitor code [ just search form] that may give you some ideas with nodemcu/lua.
I'm trying to port it to ArduinoIDE - having lots of fun