这篇文章教你备份现有设备的fastboot镜像，可以是手机，手表，电子书，甚至智能音响

优点是可以无视设备的可用空间，比如像手表的sdcard所在分区没有system大，以至于无法使用twrp备份system。以及备份的是image，还原之后可以过ota的md5验证

当然，也是有门槛的

1. 一个Unix系系统的电脑，可以是Linux或者macOS
2. adb工具（android-tools-adb）
3. fastboot工具（android-tools-fastboot）
4. 设备已解锁拥有对应twrp或是已经root

使用twrp的情况

1. 将设备启动到fastboot并连接电脑
2. 启动twrp，这里使用设备的twrp.img，如果要备份原厂recovery请别把twrp刷进去
   fastboot boot twrp.img
3. 请看备份部分

设备已root的情况

1. 将设备启动到Android并连接到电脑
2. 将adb切换到root模式
   adb root
3. 请看备份部分

备份

1. 打开一个shell
   adb shell
2. 在 /dev/block/platform 中的任意文件夹下找到找到 by-name 目录
   这里教你几个常用的Linux命令
   切换到某个目录
   cd 目录

   显示当前目录下的文件

   ls

   显示当前所在目录的路径

   pwd

   补全路径或命令 按键盘上的tab按钮

3. 这里以TicwatchPro为例，找到的路径是
   /dev/block/platform/soc/7824900.sdhci/by-name

   进去ls -l可以竖着输出目录中的文件名，拼接成这样的命令
   adb shell cat 路径/文件名 > 文件名.img
   然后拿着像vscode这种按住shift+alt（shift+option）可以同时编辑多行的编辑器操作一番，就能得到这样一堆命令(请无视>的转义，复制请自行改回来)

   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/DDR > DDR.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/aboot > aboot.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/abootbak > abootbak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/boot > boot.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/cache > cache.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/cmnlib > cmnlib.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/cmnlibbak > cmnlibbak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/config > config.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/devinfo > devinfo.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/fsc > fsc.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/fsg > fsg.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/keymaster > keymaster.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/keymasterbak > keymasterbak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/keystore > keystore.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/misc > misc.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/modem > modem.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/modemst1 > modemst1.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/modemst2 > modemst2.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/oem > oem.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/pad > pad.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/persist > persist.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/recovery > recovery.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/rpm > rpm.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/rpmbak > rpmbak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/sbl1 > sbl1.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/sbl1bak > sbl1bak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/sec > sec.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/splash > splash.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/ssd > ssd.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/system > system.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/ticnv > ticnv.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/tz > tz.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/tzbak > tzbak.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/userdata > userdata.img
   adb shell cat /dev/block/platform/soc/7824900.sdhci/by-name/vendor > vendor.img
4. 在需要存放备份的目录打开一个终端，运行第三步拼出的命令，fastboot线刷包就备份完成了