Solved !!
After much efforts and long 15 hours work, My device is working back with stock rom.
Things I Did :-
1. As YGPD tool was not detecting my phone after it was "MTK USB port" I learned how to use SP flash tool.
2. But the problem was I needed the scatter file and the other files, but I only had the .cpb official firmware file. So I did a Trick, I ran YGDP tool made the config selecting 8279W and my firmware and selected apply. This created a "down files" folder contained all the files I needed Including the scatter files. I copied everything from that folder to a new folder on the desktop. So now I had all my firware files unzipped and ready to be used with SP flash tools.
3. Then I learned how to use sp flash tool by watching couple of videos, then I thought I had give it a go. I connected the device, selected the scatter file, and from the options I selected "format all+ download" and clicked the download button. SP flash tools started doing it's work, then bar turned red, then purple then green and then is turned yellow. When it turned yellow the firmware coping was taking place. During my research about SP flash tool I read some posts here or may be somewhere else to change the USB speed setting in sp flash tools from high speed to full speed. I did changed the settings before I started the above mentioned process.
4. I did all the above procedure with my battery removed from my phone. The whole process took 30 mins. Then a green pop up with download complete. I removed the device from USB, put the battery IN and started it. The device started there was micromax logo and after couple of minutes with a screen with a blue square box and on the right hand side up and down. Then I again started the process to solve it. My research revealed that it was some factory mode stuck Issue after flashing.
I stumbled across these resources -
4.1 -
https://forum.xda-developers.com/a310/general/tutorial-factory-mode-fix-canvas-nitro-t3046390
I thought It was end to my worries finally but the zip file was hosted at that the worst "HOST" on this planet earth. I tried for an hour Trying to download it. Used VPN's proxies etc.
4.2 Second resource I stumbled across , a thread by kalyan ji but It was deserted by him. Luckily some one had quoted him in the replies so I had found what OP has written. Unfortunately he didn't made the different file host and it was hosted on the same host. This was the thread -
https://forum.xda-developers.com/a310/help/factory-mode-fix-micromax-canvas-a311-t3149215/
4.3 Third one was the GSM hosting thread, Which I'm not linking here due to possible rules Violation. Basically it talked about same thing as 4.1 and 4.2. This file that he made available was a different file but hosted on the same Host.
4.4 few other solutions were mentioned Which I didn't tried :- like using a soda rom whose link was on the modaco forum. And one other solution some mentioned in the above threads - it was a chinese site.
5. Seeing it as a dead end here, I thought I had do the half procedure without the unfactory.bat file. I connected the device - My PC had all sort of drivers - I worked at 2 machines simultaneously. Laptops had no driver Issues but flashing tool -YGDP was not working never tried SP flash tools. PC had minor driver Issues sometimes but both YGDP and sp flash tools worked on it.
This time I connected to laptop. Opened the shell as mentioned in 4.1 and 4.2 and ran the below commands
Mind it till now my phone is showing blue square on the top left and up and down on the right
5.1 adb shell
this resulted in my phone getting shut down and on the cmd screen it was now showing root:\a311:
5.2 This command really did the trick <3
fctd -b normal
The moment I entered this command my phone restarted fully - took about 4-5 minutes as it was first boot after the flash.
But along my micromax logo it still showed factory mode going from bottom to the top of the screen.
6. Now my phone started but it showed "Invalid IMEI" , Another road block so I searched again for solutions. I stumbled across various solutions.
6.1 One guy was using maui meta 3g tool to write Imei numbers but was using some database files which I didn't had when I extracted my firmware - so this was a no go for me.
6.2 Another guy was using SN and IMEI writer - here In this method also required some database and config files which I didn't had.
6.3 This was my device specific solution. Solution here -
https://www.youtube.com/watch?v=4votc0m4qDo Problem here were guy didn't gave any download link to the zip file he was using. Another Issue was he was Using a custom recovery.
The file he was using "nitro baseband + IMEI.zip" - I searched for that file and found it on the modaco forums - 2 links were alive.
Direct links to that file -
https://mega.nz/#!pIRWFT5I!GM-LWuiogIk56gsAMDg5Qp0nU2FAgamHwbSXgbbdSqc
second -
https://www.dropbox.com/s/c3t6aa1hswxkkwf/Nitro Baseband %2B IMEI Patch.zip?dl=0
7. Now I had needed the custom recovery Installed on my device. So I followed this resource -
https://forum.xda-developers.com/a310/orig-development/twrp-recovery-micromax-canvas-nitro-a311-t3066387
Problems I faced now : - Files was hosted on the same stupid host so I had to google and download the same recovery file from elsewhere. Recovery file I used as mentioned in the above link was " twrp v 2.4.4" I got the recovery file.
So now I started following one guide available here about updating the custom recovery, This One -
https://www.xda-developers.com/how-to-install-twrp/
when I reached to this step - " fastboot flash recovery twrp-2.8.x.x-xxx.img" It started waiting for device and device was never found.
8. I researched and found this could be driver Issues, I Installed the android bootloader and all other drivers, repeated the same procedure and same result. Then I noticed that when it enters the bootloader, the factory mode went from bottom to top and then fastboot appeared 2 times. I thought this is over for as factory mode is not letting me flash the new recovery and I cannot flash the IMEI patch.
So I needed the custom recovery to flash the IMEI patch to fix the Invalid IMEI Issue. But according to my thought process this factory mode Issue was not letting me do that.
9. So I searched again to fix this Issue and stumbled across this video -
https://www.youtube.com/watch?v=q4qSnpCSaFk
Link he provided for unfactory.bat files was -
http://www.mediafire.com/file/fh303sbdtsplhko/factory+mode+fix.rar
I patiently followed the steps he outlined in his video. and was able to successfully remove the factory mode Issue.
10. Now factory mode was removed I tried to again flash the recovery file via fastboot was again "waiting for device" error was received. I found One another thread here where a guy a complaining about faulty fastmode on a311 so I thought this could be the case. There were no replies to verify and I'm still in doubt about the Fast boot being faulty or not or something else ?
11. No I needed another methode to flash custom recovery I thought I had re flash everything but with a new recovery. This time I used YGDP tool to flash as my mobile was no "MTK USB port" any more. I replaced the recovery file with the recovery file I needed and re flashed it. I followed this video -
https://www.youtube.com/watch?v=fz3FcN2mvcs
12. So now I had the custom recovery device again completely started after 4-5 minutes. Surprisingly the factory mode Issue didn't came this time. I thought It has come again after flashing. I switched it off. Put the "nitroband+Imei.zip" on the SD card to install it via TWRP. I went into recovery mode TWRP loaded fine and then I installed it according to the video I linked in my points earlier. Then rebooted the system again hoping "Invalid IMEI error is gone" phone started and that error was gone
13. I turned the phone off and put my sim in and restarted it again. Everything was fine but the signals didn't came. Tried different sims and both slots, nothing worked. Then I stumbled across this link -
https://www.skyneel.com/how-to-fix-or-resolve-lost-imei-number-android-micromax-mtk-devices
14. Followed the guide and restarted it. And it worked and everything else also worked as it should have worked. Now my phone is fully functional.
I made this detailed guide for other users who have been going through various hurdles to get everything that they need at one place here. I hope that this will definitely help many users
p.s - few questions that remain - is a311's fast mode faulty ? If yes so how we can fix it.
~suresh