Thanks for your quick response.
I checked this link "https://github.com/zador-blood-stained/fel-mass-storage," but it's using segregated image (boot.scr, script.bin, u-boot-sunxi-with-spl.bin,uInitrd,zImage) for flashing EMMC. Now the problem is how to get distributed image for new armbian.img.
I downloaded armbian.img from "ftp://staging.olimex.com/Allwinner_Images/A20-OLinuXino/1.latest_mainline_images/bionic/images/"
1. Can we directly flash this armbian.img file in emmc, using any tool. Or
2. How to segregate armbian.img file into multiple files (boot.scr, script.bin, u-boot-sunxi-with-spl.bin,uInitrd,zImage). Or
3. How to get this segregated image?