开机引导模式下使用。此文说明主要适用android 6.0及以上版本
下载以下几个文件，CMD命令窗口切换到此目录就可使用了，当然还要安装USB驱动、打开USB调试（可选）：
adb工具
怎么进入此模式：手机端：电源键+音量减/加电脑端：用ADB工具，命令：adb reboot**ootloader
格式: fastboot [OPTION…] COMMAND…
版本：与1.0.41版的adb适应
flashing: 写入命令
update ZIP : Flash all partitions from an update.zip package. 如fastboot update xxx.zip , xxx.zip中包含boot.img, recovery.img,**.img等镜像文件
flashall : Flash all partitions from $ANDROID_PRODUCT_OUT. On A/B devices, flashed slot** set as active. Secondary images may**e flashed to inactive slot. 会自动搜索当前目录下的所有img文件，将它们都刷入系统对应分区。
flash PARTITION [FILENAME] : Flash given partition, using the image from $ANDROID_PRODUCT_OUT if no filename** given. 这里的PARTITION有
boot/recovery/system/userdata/cache等
basics:
devices [-l] : List devices in**ootloader (-l: with device paths).
getvar NAME : Display given**ootloader variable.
reboot [bootloader] : Reboot device.
locking/unlocking:上锁/解锁命令，将会删除个人数据
flashing lock|unlock : Lock/unlock partitions for flashing
flashing lock_critical|unlock_critical : Lock/unlock**#8216;critical’**ootloader partitions.
flashing get_unlock_ability : Check whether unlocking** allowed (1) or not(0).
advanced:
erase PARTITION : Erase a flash partition.
format[:FS_TYPE[:SIZE]] PARTITION : Format a flash partition.
set_active SLOT : Set the active slot.
oem [COMMAND…] : Execute OEM-specific command. 这里的command主要是自定义的命令（慎用）。高版本的系统可用fastboot oem help 查询有效的命令。
gsi wipe|disable : Wipe or disable a GSI installation (fastbootd only).
wipe-super [SUPER_EMPTY] : Wipe the super partition. This will reset it to contain an empty set of default dynamic partitions.
boot image: 用指定镜像文件临时启动系统，不会更改原系统的启动文件，如利用magisk加入root权限的boot文件启动
boot KERNEL [RAMDISK [SECOND]] : Download and**oot kernel from RAM.
flash:raw PARTITION KERNEL [RAMDISK [SECOND]] : Create**oot image and flash it.
–dtb DTB : Specify path to DTB for**oot image header version 2.
–cmdline CMDLINE : Override kernel command line.
–base ADDRESS : Set kernel**ase address (default: 0x10000000).
–kernel-offset : Set kernel offset (default: 0x00008000).
–ramdisk-offset : Set ramdisk offset (default: 0x01000000).
–tags-offset : Set tags offset (default: 0x00000100).
–dtb-offset : Set dtb offset (default: 0x01100000).
–page-size**YTES : Set flash page size (default: 2048).
–header-version VERSION : Set**oot image header version.
–os-version MAJOR[.MINOR[.PATCH]] : Set**oot image OS version (default: 0.0.0).
–os-patch-level YYYY-MM-DD : Set**oot image OS security patch level.
Android Things:
stage IN_FILE : Sends given file to stage for the next command.
get_staged OUT_FILE : Writes data staged**y the last command to a file.
options: 选项参数
-w : Wipe userdata.
-s tcp|udp:HOST[:PORT] : Specify a network device.
-S SIZE[K|M|G] :**reak into sparse files no larger than SIZE.
–force : Force a flash operation that may**e unsafe.
–slot SLOT : Use SLOT;**#8216;all’ for**oth slots,**#8216;other’ for non-current slot (default: current active slot).
–set-active[=SLOT] : Sets the active slot**efore rebooting.
–skip-secondary : Don’t flash secondary slots in flashall/update.
–skip-reboot : Don’t reboot device after flashing.
–disable-verity : Sets disable-verity when flashing vbmeta.
–disable-verification : Sets disable-verification when flashing vbmeta.
–unbuffered : Don’t**uffer input or output.
–verbose, -v : Verbose output.
–version : Display version.
–help, -h : Show this message.
