How to send a large amount of data faster ?

So you're a lucky guy, it's working fast for you for 2 different esp8266 based boards..
I really don't understand what's wrong with my nodemcu-e12. I don't have any other esp8266 to try. I installed mine with the same files, but using esptool. If I install last espressif firmware before, it wont make a difference, it will be erased by esptool, right ?
I still get a slow download. Honestly, I don't know where to go from here.

python esptool.py --port COM20 --baud 115200 write_flash --flash_freq 80m --flash_mode qio --flash_size 32m 0x0000 boot_v1.6.bin 0x1000 espruino_esp8266_user1.bin 0x3FC000 esp_init_data_default.bin 0x3FE000 blank.bin

 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v95 Copyright 2017 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
Flash map 4MB:512/512, manuf 0xef chip 0x4016
>Start connection process
Try Connecting to WiFi  Gardening
=undefined
Test for error
Test for error
Test for error
Test for error
Test for error
null
connected? err= null info= {
  "ip": "192.168.2.5",
  "netmask": "255.255.255.0",
  "gw": "192.168.2.1",
  "mac": "2c:3a:e8:0e:9f:1c"
 }
Wi-Fi Connected
n= 4 t: 0.006 sec
n= 3 t: 0.869 sec
[WS] "Hello to Espruino!"
n= 2 t: 1.525 sec
[WS] "Hello to Espruino!"
n= 1 t: 2.197 sec
[WS] "Hello to Espruino!"
n= 0 t: 2.859 sec
[WS] "Hello to Espruino!"