Unbrick SpreadTrum based Android phone (Micromax Bolt A27) I have a low end device i.e Micromax a27(SpreadTrum SC6820) which I m trying to restore after I had rooted it and tried to free up some space by removing the apps which broke the phone's OS.

Mistakenly I also executed a command in fastboot mode that flashed the system with a recovery.img(fastboot flash system recovery.img) after which the phone keeps on buzzing infinitely and nothing shows up on the screen.

I then tried to follow this method http://androidxda.com/flash-pac-stock-rom-android-smartphone but the phone starts buzzing endlessly when plugged in with a USB cable and nothing is shown in the status panel of tool mentioned in it (UpgradeDownload.exe)

This tool seems to extract the .img files from the .pac package(present under the firmware folder of the downloaded stock ROM) and place it in the phone,Can I somehow extract them from .pac and place them manually in the phone via fastboot?
Download research download tools, load the pac file and go in settings there you must see alls files into the pac, now it's very important: double click on system location and copy, go in your file manager, enable hidden files and paste what you have copy in file location bar in your file manager you will see all needed files