接着上个教程，同样用的罗老师的代码。
添加头文件。
添加源文件。
初始化环境。
source build/envsetup.sh
lunch
export PATH=/home/haidragon/Desktop/java-7-openjdk-amd64/bin/:$PATH
然后添加。 (代码有点老要修改下把所有的LOG宏前面加了一个字母A）
mmm ./hardware/libhardware/modules/freg/
make snod
然而驱动一般只有root用户才用访问，所以这里修改下权限。
找到ramdisk.img 文件 重新命名为.gz
命令操作如下：
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ls
android-info.txt cache.img fake_packages mkbootimg ramdisk.cpio.gz recovery symbols unmkbootimg
boot.img clean_steps.mk ×××talled-files.txt obj ramdisk.img recovery.img system userdata.img
cache data kernel previous_build_config.mk ramdisk-recovery.img root system.img zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ls
android-info.txt cache.img fake_packages mkbootimg ramdisk.cpio.gz recovery symbols unmkbootimg
boot.img clean_steps.mk ×××talled-files.txt obj ramdisk.img recovery.img system userdata.img
cache data kernel previous_build_config.mk ramdisk-recovery.img root system.img zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ll
total 478708
drwxr-xr-x 10 haidragon haidragon 4096 Jun 15 00:16 ./
drwxr-xr-x 4 haidragon haidragon 4096 May 29 23:09 ../
-rw-r--r-- 1 haidragon haidragon 25 May 29 21:51 android-info.txt
-rwxrw-rw- 1 haidragon haidragon 9078784 Jun 15 00:16 boot.img*
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:19 cache/
-rw-r--r-- 1 haidragon haidragon 13668728 May 29 22:19 cache.img
-rw-r--r-- 1 haidragon haidragon 40349 May 29 21:46 clean_steps.mk
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:19 data/
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:58 fake_packages/
-rw-r--r-- 1 haidragon haidragon 67168 May 29 22:58 ×××talled-files.txt
-rw-r--r-- 1 haidragon haidragon 8410192 Jun 15 00:16 kernel
-rwxr-xr-x 1 haidragon haidragon 58104 Jun 2 20:02 mkbootimg*
drwxr-xr-x 14 haidragon haidragon 4096 May 29 22:58 obj/
-rw-r--r-- 1 haidragon haidragon 716 May 29 21:46 previous_build_config.mk
-rw-r--r-- 1 haidragon haidragon 664636 Jun 15 00:16 ramdisk.cpio.gz
-rw-r--r-- 1 haidragon haidragon 498995 May 29 22:23 ramdisk.img
-rw-r--r-- 1 haidragon haidragon 1096536 May 29 22:39 ramdisk-recovery.img
drwxr-xr-x 3 haidragon haidragon 4096 May 29 22:39 recovery/
-rw-r--r-- 1 haidragon haidragon 9506816 May 29 22:39 recovery.img
drwxr-xr-x 9 haidragon haidragon 4096 May 29 22:23 root/
drwxr-xr-x 4 haidragon haidragon 4096 May 29 22:21 symbols/
drwxr-xr-x 14 haidragon haidragon 4096 May 29 22:43 system/
-rw-r--r-- 1 haidragon haidragon 297984228 May 29 22:58 system.img
-rwxr-xr-x 1 haidragon haidragon 13096 Jun 2 20:02 unmkbootimg*
-rw-r--r-- 1 haidragon haidragon 140614516 May 29 22:19 userdata.img
-rw-r--r-- 1 haidragon haidragon 8410664 Jun 15 00:16 zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mv ./ramdisk.
ramdisk.cpio.gz ramdisk.img
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mv ./ramdisk.
ramdisk.cpio.gz ramdisk.img
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mv ./ramdisk.
ramdisk.cpio.gz ramdisk.img
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mv ./ramdisk.img ./ramdisk.img.gz
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ls
android-info.txt cache.img fake_packages mkbootimg ramdisk.cpio.gz recovery symbols unmkbootimg
boot.img clean_steps.mk ×××talled-files.txt obj ramdisk.img.gz recovery.img system userdata.img
cache data kernel previous_build_config.mk ramdisk-recovery.img root system.img zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ll
total 478708
drwxr-xr-x 10 haidragon haidragon 4096 Jun 15 01:38 ./
drwxr-xr-x 4 haidragon haidragon 4096 May 29 23:09 ../
-rw-r--r-- 1 haidragon haidragon 25 May 29 21:51 android-info.txt
-rwxrw-rw- 1 haidragon haidragon 9078784 Jun 15 00:16 boot.img*
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:19 cache/
-rw-r--r-- 1 haidragon haidragon 13668728 May 29 22:19 cache.img
-rw-r--r-- 1 haidragon haidragon 40349 May 29 21:46 clean_steps.mk
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:19 data/
drwxr-xr-x 2 haidragon haidragon 4096 May 29 22:58 fake_packages/
-rw-r--r-- 1 haidragon haidragon 67168 May 29 22:58 ×××talled-files.txt
-rw-r--r-- 1 haidragon haidragon 8410192 Jun 15 00:16 kernel
-rwxr-xr-x 1 haidragon haidragon 58104 Jun 2 20:02 mkbootimg*
drwxr-xr-x 14 haidragon haidragon 4096 May 29 22:58 obj/
-rw-r--r-- 1 haidragon haidragon 716 May 29 21:46 previous_build_config.mk
-rw-r--r-- 1 haidragon haidragon 664636 Jun 15 00:16 ramdisk.cpio.gz
-rw-r--r-- 1 haidragon haidragon 498995 May 29 22:23 ramdisk.img.gz
-rw-r--r-- 1 haidragon haidragon 1096536 May 29 22:39 ramdisk-recovery.img
drwxr-xr-x 3 haidragon haidragon 4096 May 29 22:39 recovery/
-rw-r--r-- 1 haidragon haidragon 9506816 May 29 22:39 recovery.img
drwxr-xr-x 9 haidragon haidragon 4096 May 29 22:23 root/
drwxr-xr-x 4 haidragon haidragon 4096 May 29 22:21 symbols/
drwxr-xr-x 14 haidragon haidragon 4096 May 29 22:43 system/
-rw-r--r-- 1 haidragon haidragon 297984228 May 29 22:58 system.img
-rwxr-xr-x 1 haidragon haidragon 13096 Jun 2 20:02 unmkbootimg*
-rw-r--r-- 1 haidragon haidragon 140614516 May 29 22:19 userdata.img
-rw-r--r-- 1 haidragon haidragon 8410664 Jun 15 00:16 zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ gunzip ./ramdisk.img.gz
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mkdir ramdisk
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ cd ./ramdisk/
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead/ramdisk$ cpio -i -F ../ramdisk.img
1760 blocks
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead/ramdisk$ rm -f ../ramdisk.img
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead/ramdisk$ find . | cpio -o - H newc > ../ramdisk.img.unzip
cpio: Too many arguments
Try 'cpio --help' or 'cpio --usage' for more information.
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead/ramdisk$ find . | cpio -o -H newc > ../ramdisk.img.unzip
1760 blocks
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead/ramdisk$ cd ..
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ gz
gzexe gzip
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ gzip -c ./ramdisk.img.unzip >./ramdisk.img.gz
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ rm -f ./ramdisk.img.unzip
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ rm -R ./ramdisk
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ mv ./ramdisk.img.gz ./ramdisk.img
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ ls
android-info.txt cache.img fake_packages mkbootimg ramdisk.cpio.gz recovery symbols unmkbootimg
boot.img clean_steps.mk ×××talled-files.txt obj ramdisk.img recovery.img system userdata.img
cache data kernel previous_build_config.mk ramdisk-recovery.img root system.img zImage-dtb
haidragon@ubuntu:~/Desktop/android/out/target/product/hammerhead$ 把system.img和ramdisk.img 重新刷入手机。（ramdisk.img这个是要重新打包到boot.img）
效果：