NodeMCU v2 - 1. setup env

1. download FW 0.9.5
    integer : integer version only support integer as lua number.
2. download FW flash tool
    >. Config : click gear btn to select FW, offset = 0x0000
    >. Flash, you may try hold flash btn, and press RST btn
3. upload should be started


Another way to update FW
1. download tool
2. Run tool, setup
    a. SPI MODE = DIO
    b. FLASH SIZE = 32M
    c. ADDR = 0x00000
    d. baudrate, 9600(main), 115200(dev)
3. Press START btn
4. hold flash btn, and press RST btn on the NodeMCU board
5. it should be started

After update FW, open com port with teraterm or other tool
master version baudrate = 9600, dev version baudrate = 115200
You will get
    NodeMCU 0.9.5 build 20150318  powered by Lua 5.1.4
    lua: cannot open init.lua
    >
Now, try to enter
    print("Hollo NodeMCU")
You will get
    > print("Hello NodeMCU")
    Hello NodeMCU

又被我踩到地雷，更新0.9.6_dev後，上電都是MEM Check fail!
燒回0.9.5後就好了

Other Resource :
NodeMCU github
ESPressif