How to make your own SD-bootable ROM
1 Make Linux Image Files for 4418/6818
The key point is to make the boot section in the SD card to a boot.img and the rootfs section in the SD card to a rootfs.img and replace the corresponding files in an eflasher. Run the following commands on a PC host:
1) Download https://github.com/friendlyarm/debian_nanopi2;
2) Copy all the files in your SD card's boot section to "debian_nanopi2/boot" and all the files in your SD card's rootfs section to "debian_nanopi2/rootfs";
You can make changes in these two directories according to your requirements.
We suggest you remove the "etc/fs.resized" file under the rootfs directory to allow system's automatic file system extension.
3) Make an img file with the make_ext4fs utility under "debian_nanopi2":
./tools/make_ext4fs -s -l 67108864 -a root -L boot boot.img boot
./tools/make_ext4fs -s -l 2097152000 -a root -L rootfs rootfs.img rootfs
4) Copy the newly generated boot.img and root.img to the "core-gte" directory of an eflasher's FAT section and this eflasher will be ready for use
2 Make Linux Image Files for H3/H5
The key point is to make the boot section in the SD card to a boot.img and the rootfs section in the SD card to a rootfs.img and replace the corresponding files in an eflasher. Run the following commands on a PC host:
1) Download utilities: EFlasher-build-tools;
2) Make an ext4 formatted img file with the rootfs section:
$ ./make_ext4fs -s -l 2097152000 -a root -L /SD/rootfs rootfs.img rootfs
-l specifies the size of an img file and the unit is Byte, 2097152000 Byte=2000MB. The specified size must be bigger than the actual size of a source directory.
3) 将待烧写 boot 分区目录制作为 fat 格式的 img 文件:
$ ./build-boot-fat.sh boot.img /SD/boot 40
40 表示boot.img的大小为40M。
4) 用新生成的boot.img和root.img替换eflasher-ROM的FAT分区对应系统目录下的同名文件，然后参考前面的步骤进行烧写即可;
3 用自制系统制作可启动的SD卡或者SD卡映象
在产品量产阶段，通常需要为自已的定制过的产品制作专用的系统映象，这里的系统映象是指 Android编译生成的 boot.img、system.img，或者Ubuntu的根文件系统 rootfs.img 等等。
这个章节将介绍如何用自已编译的系统映象，制作一张可以启动的SD卡，或者，制作一个完整的系统映象文件，完整的系统映象可用于产品量产时批量生成SD卡。
下面以制作S5P4418 Android 启动卡为例，命令如下：
git clone https://github.com/friendlyarm/sd-fuse_nanopi2.git cd sd-fuse_nanopi2 wget http://112.124.9.243/dvdfiles/S5P4418/images-for-eflasher/android-lollipop-images.tgz tar xvzf android-lollipop-images.tgz
注：如果是S5P6818，你需要将sd-fuse_nanopi2.git改为sd-fuse_nanopi3.git，S5P4418改为S5P6818。
现在，请将自已编译生成的 Android映象替换掉Android目录下的同名文件，然后用以下命令制作一张可以启动的SD卡:
sudo ./fusing.sh /dev/sde android
注：请将/dev/sde替换为真实的SD卡设备名称。
如果要制成一个完整的系统映象文件，命令改为:
sudo ./mkimage.sh android
