A few months ago, i did bought a chinese version of NodeMCU named LOLin V3, it's not version of 3 of NodeMCU, it's using CH340G chip which is the TTL to USB converter made by a chinese manufacture instead of the FTDI. After using for few times, it's stopped working.

LOLin V3

Install the esptool

We need to download and install the esptool that will help us the new flash the new firmware

$ git clone https://github.com/themadinventor/esptool.git
$ cd esptool
$ python setup.py install

Downloading the firmware

You can grab the latest .bin version of the firmware from the github repo, or use nodemcu-build to build a custom firmware.

Flashing the firmware

First, you need to know is the USB port where the board is plugged, open the commandline, then use the esptool to flash the new firmware :

$ python esptool.py --port /dev/ttyUSB0 --baud 9600 write_flash --flash_mode qio --flash_size 32m --flash_freq 40m 0x00000 nodemcu_float_0.9.6-dev_20150704.bin
esptool.py v1.0.2-dev
Running Cesanta flasher stub...
Flash params set to 0x0040
Writing 450560 @ 0x0... 450560 (100 %)
Wrote 450560 bytes at 0x0 in 19.5 seconds (184.5 kbit/s)...

Once the flashing is done, just open ESPlorer, set the USB port and the baud speed then hit Open :