OpenWrt building for Linkit 7688 and 7688 Duo

After describing the general specifications of the two boards in the previous article

Linkit 7688 and 7688 Duo Development Boards

now we build the OpenWrt image from the sources. The following link describes the steps

Building the firmware from the source code

First we have to create the folder Linkit under /home/sviluppo in a shell command window in our Debian image, already used to  build OpenWrt in another article

Building OpenWrt Image

Install the prerequisites

Clone the OpenWrt repository

In the shell command window go to the openwrt folder and copy feeds.conf.default file as feeds.conf

Add the Mediatek feed for the boards

Update the feeds  for the packages

Install the packages

Configure the kernel executing

Use the following settings

  • Target System: Ralink RT288x/RT3xxx
  • Subtarget: MT7688 based boards
  • Target Profile: LinkIt7688

menuconfigSave and exit.

Run the building

At a certain point, the building generates an error for the wireless card libraries. Mediatek has not released the wireless card sources, but an sdk with compiled binaries for a kernel version  different from the one we are using in the building; the error reported is

One way to fix the problem is the following.

Go to the  /home/sviluppo/Linkit/openwrt/feeds/linkit/mtk-sdk-wifi/wifi_binary/  folder and copy the files for our kernel version

Rerun the building. At the end of the process the generated file is available in the  bin/ramips folder

linkit imageThe built firmware is available here

OpenWrt Linkit 7688 and 7688 Duo Image

WARNING: The image installation on the device is at your own risk. We accept no responsibility if the installation leads to  malfunction or block of the device.

If you upgrade the board using an usb flah drive, you need to rename the openwrt-ramips-mt7688-LinkIt7688-squashfs-sysupgrade.bin file in lks7688.img.

The image kernel for this building  is  3.18_45; If you want to use a recent kernel, you must use the opensource drivers available for the board; in the case of the Linkit 7688 Duo card, in our possession, we can rebuild the image using the Realtek rt76 drivers for the wireless network adapter and add the additional components for the Atmel MCU using LEDE, an OpenWrt fork

LEDE Project

In the next article you will build  a LEDE image for the Linkit 7688 Duo board. For the Linkit 7688 board at this time, the mraa libraries, used to interface the periphals, are not yet compatible with the latest version of LEDE and the functionality of the image is limited. There may be also bugs in the  wireless card opensource drivers, which hopefully are solved in the refinement of these drivers.

 LEDE building for Linkit 7688 Duo