Memory layout of eMMC at BBB

Hi,

Anybody know memory layout of eMMC at BBB?

I want update via TFTP eMMC with new versions of u-boot, linux kernel, dtb and RFS:

U-Boot # mmc dev 1 part 0
U-Boot # tftpboot ${loadaddr} MLO
U-Boot # mmc write ${loadaddr} 0x100 0x100
U-Boot # mmc write ${loadaddr} 0x200 0x100
U-Boot # tftpboot ${loadaddr} u-boot.img
U-Boot # mmc write ${loadaddr} 0x300 0x400

BUT I need start address and size for uImage, for dtb file and for RFS:

U-Boot # tftpboot ${loadaddr} uImage
U-Boot # mmc write ${loadaddr} ??? ???
U-Boot # tftpboot ${loadaddr} am335x-boneblack.dtb
U-Boot # mmc write ${loadaddr} ??? ???
U-Boot # tftpboot ${loadaddr} myrootfsfile
U-Boot # mmc write ${loadaddr} ??? ???

Any ideas?