It will be very convenient for us to make the file system which we build well the environment we need on pcDuino to our own exclusive pcDuino firmware. Then we will no longer worry about if there will meet some problem with the pcDuino  to re brush the pcDuino system.

In this post I will demo for you.

Firstly, we need to prepare a USB to TTL module as the figure to connect pcDuino with the Computer.

Then open the serial tool on computer ( here we use Xshell ) according to your own condition to modify it, the serial port normal setting as the figure

Then power for pcDuino, keep pressing any keys on the keyboard when booting the system to avoid the system enter into U-BOOT

Input the following commands，enter into initramfs

> setenv loglevel 8 ramfs
> run bootcmd

Then it will prompt “login”， input root to enter

Instal TF card ( not less than 4GB), input following commands to check the pcDuino partition

cat /proc/partitions

Let mmcblk0 partition mount to /mnt direction

> mount /dev/mmcblk0 /mnt

最后进入到挂载的TF卡路径中，使用DD指令把nandd里面的文件系统制作成img文件就成了我们专属的pcDuino固件了

At last, enter into the mount TF card path, use DD commands brush the file in nandd to img file, then our own exclusive pcDuino firmware is done

> cd /mnt
> dd if=/dev/nandd of=/mnt/pcduino3_ubuntu_20140912.img bs=4M

The final brush ways of img file  is same with official brush way of  img file, but the imag file is about 4GB size.