First, what is the brush machine?
"Brush" is the word often heard in everyday life, for example, some people say "my phone very slow, need to re-swipe machine", "My phone does not support this feature, you can go to brush it under the machine," and so on. In fact, professional point, Brush is to re-re-deployed in uboot onboard iNand / Nand / SD cards and other storage devices above, kernel, rootfs. Popular point is that reloading an operating system, like the computer to reinstall the system as above.
Second, prepare Brush tool.
(A) software tools
1, fastboot: Brush tool is now generally use the fastboot, both in the development board or the phone. fastboot is a Brush tool in a windows, but also uboot following a command, when executed "fastboot" in uboot, uboot is equivalent to the following fastboot Windows software management, simply use fastboot command execution software in Windows mirroring can be realized programmer "brush."
2, fastboot drivers: Install fastboot fastboot doubtless need to install the drivers friends.
3, DNW tool: DNW Brush mode to use. Samsung Mirror burning software, its role is to direct the image to burn to the specified address SRAM / DDR go. (Note: It is burned into SRAM / DDR, rather than iNand / Nand / SD card, the data will be cleared after power failure)
4, DNW drive: supporting the DNW use with USB-OTG.
5, Jiuding initiatives in SD card programmer tools: SD card Brush way to use flashing mirror, the mirror will burn directly to an SD card above, Jiuding company is a SD card burning software.
6, secureCRT: uboot printing of information display serial port, but also an important tool uboot console display.
7, serial port driver: supporting serial cable to use with secureCRT.
(B) hardware tools
1, serial cable: PC Boards and connecting bridge.
2, USB-OTG line: when using the mirror to burn.
3, SD Card: SD card mode brush to use.
Third, the introduction of three kinds of brush mode.
(A) fastboot Brush, Brush premise of this approach is that you can start the development board and into uboot uboot console. This is also the most mobile phones Brush.
(B) DNW + fastboot brush, when you can not start uboot development board, also known as the "brick" on the use of in this way, this way to burn a uboot image after the start uboot into the console brush fastboot reuse.
(C) SD card + fastboot Brush, ibid., Also for the development board can not start uboot this case, and after the start uboot uboot programmed into the console and then use fastboot mode Brush.
Fourth, start brushing machine.
(A) the fastboot brush.
1, the development board startup mode selection switch to the SD card method.
2, connected by USB cable OTG interface, serial line to ensure that the serial port 2, open SecureCRT software.
3, SecureCRT software, according to the configuration of FIG. com few can see your device's own port manager there.
4, start the development plate, and count down the console between the end of the fast pressing the Enter key for 3 seconds, press the fastboot, appear as shown.
5, windows key + R and type cmd into the windows console, enter the directory where you installed the fastboot (I installed the fastboot file under the name A custom disk folder), so A: A to enter the disk, and then cd fastboot.
6, fastboot devices to see whether the device is connected successfully, the next figure shows the connection appears successful.
7, the prepared uboot, kernel, rootfs ready to establish a folder into the installation directory fastboot, I am here to programming android4.04 as an example, the following command fastboot turn down:
// 烧录uboot
fastboot flash bootloader android4.0.4/uboot.bin
// 烧录kernel
fastboot flash kernel android4.0.4/zImage-android
// 烧录android rom
fastboot flash system android4.0.4/x210.img
8, after the implementation of the development board can see over there is a progress screen above, When the programming is complete, execute fastboot reboot restart, start a android4.0.4 system, you're done.
(Ii) DNW + fastboot brush.
1, the development board switch to start the USB mode selection mode.
2, hold down the power key development board, DNW software appears next chart [USB: OK] indicates that the drive to work, and can be programmed to prepare the uboot.
3, is provided at Configuration-> Options Down Address is 0xd0020010, following FIG.
4、按住开发板POWER键（不可松开），点击DNW软件的USB Port->Transmit选择x210_usb.bin镜像的全路径，下载。注意：下载以后还是不能松开POWER按键，因为还没下载uboot镜像，至于有一些步骤为什么要这样做，我在后面继续给大家说明原因。
5、按照第4步，设置地址为0x23e00000，选择uboot镜像并且下载。uboot镜像下载成功以后你就可以松开手了。
6、松开手以后就已经进入uboot了，然后就按照fastboot方式刷机为这块“砖头”刷上一个操作系统。
（三）SD卡+fastboot刷机。
1、首先打开九鼎创展的SD卡烧写工具，然后Browse选择uboot.bin镜像的路径，选择路径以后一定不能急着按START烧录，需要按一下ADD添加才会将刚刚的路径添加进去，这也是这个软件的恶心之处，然后再按START，出现“Fusing image done”，如下图，就是烧录成功了。
2、然后将开关打到SD卡方式，开机，便可启动uboot，出现uboot的控制台，然后按照fastboot方式重新烧写一个操作系统。
五、一些步骤的原因。
1、为什么在DNW烧录的时候需要先烧录一个x210_usb.bin文件呢？
答：因为DNW是烧录到SRAM/DDR中去的，SRAM是很小的只有16KB，放不下整个uboot，所以先要烧录一小段程序初始化开发板的DDR，也就是BL1，然后再把整个uboot烧录到DDR里面去。
2、为什么这几种方式刷机最后还是需要使用到fastboot？
答：因为这几种方式都是先让开发板有一个uboot，然后依靠uboot下的控制台连接windows上面的fastboot再使用命令把镜像烧录的。当然，还有其它的方式例如可以直接tftp方式也可以直接将这些镜像下载到本地。
3、DNW下载时为什么要一直按着POWER按键？
答：因为DNW下载时将镜像下载到SRAM/DDR的，它们都是掉电不保存的，所以不按着POWER按键就会让刚刚下载的内容丢失，当下载了uboot以后不用按着是因为uboot里面有一段代码是初始化开发板的供电锁存，uboot运行以后就不用一直用手按着给开发板供电了。
4、DNW下载两个镜像的地址为什么相差那么远？
答：下载第一个镜像的地址是内部SRAM的地址，当下载第一个镜像以后就会初始化了外部的DDR，所以下载第二个镜像的地址是外部的DDR的地址。
六、可能遇到的问题。
1、使用SD卡的时候烧录不进去？
答：烧录不进去的原因可能是：①SD卡烧录软件有问题，可以尝试一些以管理员权限运行。②SD卡有问题，注意SD卡上有个写保护，不要把开关打到那里去了。③其它的问题，可自行百度。
2、dnw驱动安装不了？
答：win10系统增加了一些驱动的强制签名，所以一些驱动没有经过微软同意就不能安装，破解方法是关闭强制签名然后再安装驱动。具体见：
https://jingyan.baidu.com/article/624e74594dbc8d34e8ba5aa6.html
3、串口终端输入fastboot后出现 error：no MBR is found at SD/MMC？
答：SD卡/INAND/NAND里面没有一个对uboot有一个分区信息表，需要fdisk -c 0去重新分区，然后再fastboot。
4、dnw刷机时刷不进去，进度条不动？
答：①重写地址（即使你的地址正确），多试几遍就好。②重启开发板，重刷。
