About Fastboot and eMMC :
U-boot Configuration
To configure fastboot for eMMC/SD flashing, make sure that CONFIG_FASTBOOT_NAND is not defined, CONFIG_STORAGE_EMMC is defined and CONFIG_MMC_FASTBOOT_DEV is set to appropriate MMC slot number on which eMMC is connected in u-boot/include/configs/am335x_evm.h file before building u-boot source.
But i search the u-boot source code , can't found about CONFIG_STORAGE_EMMC and CONFIG_MMC_FASTBOOT_DEV .
What i missing ?