This section describes how to build the bootloader for LinkIt Smart 7688 and LinkIt Smart 7688 Duo development boards from source codes.

Environment

The following operations are performed under a Ubuntu LTS 14.04.3 environment. For a Windows or a Mac OS X host computer, you can install a virtual machine to have the same environment:

• Download Ubuntu 14.04.3 LTS image from http://www.ubuntu.com.
• Install this image with VirtualBox (http://virtualbox.org) on the host machine. 50GB disk space reserved for the virtual machine is recommended.

Steps

In the Ubuntu system, open the Terminal application and enter the following commands:

1. Refer to Step 1 of the firmware building process for installing all prerequisite packages.
2. Download the bootloader source codes:

   $ git clone https://github.com/MediaTek-Labs/linkit-smart-uboot.git 

3. Change to the source folder:

   $ cd linkit-smart-uboot  

4. Install the toolchain to build the bootloader:

   $ sudo tar xjf buildroot-gcc342.tar.bz2 -C /opt/  

5. Since the toolchain is provided in 32-bit executables, you need to install additional packages for execution on a 64-bit machine:

   $ sudo dpkg --add-architecture i386   
   $ sudo apt-get update   
   $ sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 

6. Start the compilation process:

   $ make  

7. The resulted bootloader file is uboot.bin.
8. You can rename it to lks7688.ldr to update the system bootloader through a USB drive.