Unlocking fastboot of Coolpad Note 3

I have a Coolpad Note 3 and I am trying to unlock the fastboot (bootloader).
Everything is perfectly setup on my Laptop except for one thing that I cannot install recoveries or flash my device through Sp Flash tool.
I have Ubuntu 16.04 LTS on my laptop. Surprisingly I can use adb and connect my phone wired or wirelessly while I develop and test my apps through Android Studio. Although I had no luck with Unity remote for developing and testing through Unity 5.x versions.
I mean that I can connect my phone to my laptop and test apps over WiFi/Wire cause I and it works perfect and I can use adb commands through the terminal as well. Only problem is I cannot use fastboot. Actually running fastboot in the terminal produces the regular output it should i.e.

$ fastboot


usage: fastboot [ <option> ] <command>

commands:

update <filename>                        reflash device from update.zip

flashall                                 flash boot, system, vendor and if 
found,

                                       recovery

flash <partition> [ <filename> ]         write a file to a flash partition

erase <partition>                        erase a flash partition

format[:[<fs type>][:[<size>]] <partition> format a flash partition.
                                       Can override the fs type and/or
                                       size the bootloader reports.

 getvar <variable>                        display a bootloader variable

boot <kernel> [ <ramdisk> [ <second> ] ] download and boot kernel

flash:raw boot <kernel> [ <ramdisk> [ <second> ] ] create bootimage and 

                                           flash it

devices                                  list all connected devices

continue                                 continue with autoboot

reboot                                   reboot device normally

reboot-bootloader                        reboot device into bootloader

help                                     show this help message



options:

-w                                       erase userdata and cache (and 
format

                                       if supported by partition type)

-u                                       do not first erase partition 
before

                                       formatting



-s <specific device>                     specify device serial number
                                       or path to device port

-l                                       with "devices", lists device 
paths
-p <product>                             specify product name
-c <cmdline>                             override kernel commandline
-i <vendor id>                           specify a custom USB vendor id
-b <base_addr>                           specify a custom kernel base                   
address.
                                       default: 0x10000000

-n <page size>                           specify the nand page size.
                                       default: 2048


-S <size>[K|M|G]                         automatically sparse files 
greater

                                       than size.  0 to disable

Using fastboot devices in terminal has no output.
Same results for sudo fastboot devices and I even tried $(which fastboot) devices and sudo $(which fastboot) devices. No luck on my end.

My Android phone is :
Coolpad Note 3
Running Marshmallow Stock ROM
Rom is unmodified and stock
Phone is not rooted.
Also no custom software like a recovery

Can anybody help me with running fastboot with my Coolpad Note 3.

I found a simple workaround following this method listed on this website here :
http://abhisek.github.io/coolpad_note3/porting/2015/11/05/unlocking-the-bootloader.html

What I did for my solution based on the websites instructions

First I booted up my phone normally.
Connect it to your laptop or PC (if you are still using one)
Fire up a terminal (on Ubuntu) or minimal ADB for windows (sorry I don't know for MacOS)

type adb reboot bootloader

As soon as I booted into bootloader I enter

fastboot -i 0x1ebf devices into the terminal and I could successfully see the following output:

devicefastbootidhere fastboot

where devicefastbootidhere is the fastboot id of your android device

then I tried to unlock the oem

$ fastboot -i 0x1ebf oem unlock

and was shot down with the following output :

...
FAILED (remote: unknown command)
finished. total time: 0.002s

I tried not to lose any hope despite the failure:
( The website says that on Coolpad Note 3 like devices you have to enable the option to unlock the oem from the Developer settings ... more on that in the link above )

What worked for me was that my Coolpad Note 3 was running Marshmallow and CoolUI 6.0. older version of my device i.e. my device Coolpad Note 3 was originally shipped with Lollipop as stock Firmware. I manually have flashed the new Marshmallow Stock ROM. What I did next was lucky for me. I do hope other Coolpad users get it right too.

I used fastboot -i 0x1ebf flash recovery /path/to/recovery_twrp.img

and I was greeted with the following output;

target reported max download size of 134217728 bytes
sending 'recovery' (16384 KB)...
OKAY [  1.683s]
writing 'recovery'...
finished. total time: 1.686s

On the website above the author mentions additional steps to follow to flash recovery on Coolpad Note 3 through fastboot but I didn't had to follow them. I was actually successfull in flashing recovery through fastboot. But for every fastboot command I have to use

fastboot -i 0x1ebf <command here> <options> this method.