概述在酷安看到一张表情包，素材是MIUI fastboot界面图片，但是不够清晰，于是考虑自己提取。
原理
splash.img (or splash.bin or logo.img or logo.bin) is the raw file in which the boot logo (splash screen - the picture displayed when the device is booted) is stored.It is stored under the partition: splash or logo in many Snapdragon devices (might vary for devices)
MTK导出logo分区1dd if=/dev/block/bootdevice/by-name/logo of=/sdcard/logo.bin
提取图片使用LogoBuilder提取。
高通导出splash分区1dd if=/dev/block/bootdevice/by-name/splash of=/sdcard/splash.img
提取图片使用binwalk分析splash.img （建议使用Linux操作）
1binwalk -e splash.img
结果类似于：
123456DECIMAL HEXADECIMAL DESCRIPTION--------------------------------------------------------------------------------16384 0x4000 PC bitmap, Windows 3.x format,, 1080 x 1920 x 246237238 0x5F2C36 PC bitmap, Windows 3.x format,, 1080 x 1920 x 2412458092 0xBE186C PC bitmap, Windows 3.x format,, 1080 x 1920 x 2418678946 0x11D04A2 PC bitmap, Windows 3.x format,, 1080 x 1920 x 24
然后使用dd命令或十六进制编辑器，提取BMP图片即可。
结果2040x1080：1920x1080：
参考[GUIDE] How to Change Boot Logo (Splash Screen) for Snapdragon Devices (splash.img)Changing boot logo (logo.bin) program