1.  Toolchain
    Toolchain is define by CROSS_COMPILE in the file Makefile now, you modify or add your default toolchain path.

2.  Configure the rk platform
    rockchip support for uboot chip set configs as:
        configs\rk3288_defconfig
        configs\rk3036_defconfig
        configs\rk3126_defconfig
        configs\rk3128_defconfig

    example:
        make rk3288_defconfig	-	Command to configure rk3288 platform for uboot.

3.  Build
	make			-	Command to make rk uboot bin.

4.  Clean
	make clean
	make distclean		-	Command to clean all include config.

5.  rk uboot bin
    if uboot as first level bootloader, rk uboot just a bin, such as:
        RK3288Loader_uboot_V2.17.01.bin

    if uboot as second level bootloader, rk uboot just a image, such as:
	uboot.img
    define CONFIG_SECOND_LEVEL_BOOTLOADER configure uboot as second level bootloader,
    if define CONFIG_MERGER_MINILOADER, rk uboot will merge mini loader bin which as first level bootloader, such as:
        RK312xLoader_miniall_V2.17.08.bin	-	fist level bootloader
	uboot.img				-	second level bootloader

6.  Chipset
    support RK3288,RK3036,RK3126,RK3128.

7.  Storage
    support emmc, sdcard and nand flash.

8.  configure file
    rk uboot configure files as:
        include\configs\rk_default_config.h	-	define all rk default module, just a common file.
        include\configs\rk30plat.h		-	define detail configure for rk30 plat: rk3036, rk3126, rk3128
        include\configs\rk32plat.h		-	define detail configure for rk32 plat: rk3288

9.  maskrom mode
    if storage hasn't program rk first level bootloader, power on will enter maskrom mode, prepare for bootloader download.

10. rockusb mode
    rk rockusb mode is using for down rk other images, such as kernel.img and so on.

11. Fastboot
    Android fastboot, all command as:
        fastboot support below command
        fastboot getvar version
        fastboot getvar version-bootloader
        fastboot getvar unlocked
        fastboot getvar secure
        fastboot getvar product
        fastboot getvar serialno
        fastboot getvar partition-type:<partition_name>
        fastboot getvar partition-size:<partition_name>
        fastboot oem recovery
        fastboot oem recovery:wipe_data
        fastboot oem unlock
        fastboot oem unlock_accept
        fastboot oem lock
        fastboot flash <partition_name> [ <filename> ]
        fastboot reboot
        fastboot reboot-bootloader
        fastboot continue
        fastboot boot <kernel> [ <ramdisk> ]
        fastboot update <filename> (this file should use make updatepackage in android root directory to generate it)
        fastboot flashall