Recover hard-bricked device (Karbonn a4)

I recently agreed to help a friend on repairing his mobile and I succeeded. but I tried different options and mistakenly deleted the system files. so now all that displays is the boot logo and goes directly into recovery mode. Can anybody help me to recover it? better, if someone could provide me with a backup from the same model so I can simply apply it from SD card.
P.S. it was rooted before going into hard brick stage!