Booting android file system from SD card

1.Find device node for the SD card
2.Unmount it first, if it mounted automatically..
3.Format it by using mke2fs command
4.Create the partition table by using fdisk command
5.Use mkfs.ext2 for that partition
6.Load the file system to SD card after mounting it in the host system
7.Unmount the card.
8.The card is ready for booting