Hello Ninad,
After extracting A70.zip there were tow files boot.img and system.img.
I copied both files on SD card and followed the process mentioned by you, below are the detail of the same.
Checking MD5 sums...
Erasing boot before restore...
Restoring boot image...
Restoring image...
Restoring .android_secure...
Restoring cache...
sd-ext.img not found. Skipping restore of /sd-ext
Restore complete!
After rebooting again the phone is stuck up at the bootscreen
Note: My SD card do not have any kind of partition