VAR-SOM-MX6 Android KK R01

From Variscite Wiki
VAR-SOM-MX6 Android-KK-4.4.2 100 r1 Developers Guide


This is the first Android KK release for VAR-SOM-MX6, Android-KK-4.4.2 100. This version only supports VAR-SOM-MX6 Quad/Dual. Solo and Dualite support will be added in the coming few weeks.

The explanations are is splitted into 3 platforms : Q, DL and Solo to enable better tuning  for som based parameters.
We have changed the build procedure to be more automatic, for simplicity.


The objective of this document is to guide VAR-SOM-MX6 Android developers to obtain Android KitKat sources, setting up host environment, compilation and deployment.

This document contains instructions for:

  • Hardware and software requirements.
  • Setup the hardware.
  • Setup the toolchain.
  • Download & build the sources.
  • Install the binaries on the VAR-SOM-MX6 SOM.

Document Reference

This release is based on Freescale Rev android_kk4.4.2_1.0.0-ga, 07/2014 release. Please download and read the documents android_kk4.4.2_1.0.0-ga_docs.tar.

  • Android User's Guide
  • Android Quick Start Guide
  • Android Release Notes
  • Android Frequently Asked Questions

Supported hardware and features

Board support
CPU (Only Quad supported)

i.MX6 Quad Solo and dual lite will be supported within 2 weeks

Software platform

Freescale Android-KK-4.4.2 100

Nand Recovery Will be available in next release, once all SOMs version are supported.
NAND Flash size support
0.5,1.0,2.0 GB
Wired Network
10/100/1000 Mbps Ethernet
Wireless Network
802.11 b/g/n
USB host
Host and Device
x3, up to 3.6 Mbps.
Display HDMI 720P,1080P LVDS0 (On board LVDS to RGB bridge, EVK supports 800x480 resolution) LVDS1 external display
Audio Line IN/ Line out
Camera ov5640 camera sensor. CB402 board can be ordered seperately at :

Hardware Requirements

VAR-SOM-MX6 evaluation kit.

Host (PC) setup requirements

The host development environment for Android is based on Ubuntu, please install Ubuntu version 12.04 64bit LTS


Do not use other Ubuntu releases, other than recommended above.

For 64-bit Ubuntu 12.04

The complete Android host requirments: Also the instruction are in Freescale "Android User's Guide" manual.

The following command installs the required packages for setting up the android build host:

$ sudo apt-get install libgl1-mesa-dri
$ sudo apt-get install git gnupg flex bison gperf build-essential \
  zip curl libc6-dev libncurses5-dev:i386 x11proto-core-dev \
  libx11-dev:i386 libreadline6-dev:i386 libgl1-mesa-glx:i386 \
  libgl1-mesa-dev g++-multilib mingw32 tofrodos \
  python-markdown libxml2-utils xsltproc zlib1g-dev:i386
$ sudo ln -s /usr/lib/i386-linux-gnu/mesa/ /usr/lib/i386-linux-gnu/

In addition to the packages requested on the Android website, the following packages are also needed:

Installing the JDK

The Sun JDK is no longer in Ubuntu's main package repository. In order to download it, you need to add the appropriate repository and indicate which JDK should be used.

Please follow the link for the java install:

Additional packages

In addition to the packages requested on the Android website, the following packages are also required:

$ sudo apt-get install uuid uuid-dev
$ sudo apt-get install zlib1g-dev liblz-dev
$ sudo apt-get install liblzo2-2 liblzo2-dev
$ sudo add-apt-repository ppa:git-core/ppa
$ sudo apt-get update
$ sudo apt-get install git-core curl
$ sudo apt-get install uboot-mkimage
The build machine should have at least 30GB of free space to complete the build process.
Please refer to the AOSP documentation for latest information and instructions for setting up other Ubuntu versions

Comment for build error: If this is the first time you build on a 64bit machine you may encounter some error releated to lzo library and other. has detail information how to fix this.

Obtain source code

Variscite provides an Android Release Package for the VAR-SOM-MX6. The Linux kernel and U-Boot are available through GITHUB.

The Android KK installer Package for the VAR-SOM-MX6 can be obtained from Variscite's FTP, under: /VAR-SOM-MX6/Software/Android_KK/Android-KK4.4.2_Release_100/

  • android_kk4.4.2_1.0.0-ga_core_source.tar.gz - Freescale's i.MX6 KK4.4.2_100 original patch files.
  • android_kk4.4.2_1.0.0-ga_docs.tar.gz - Freescale i.MX6 KK4.4.2_100 documents
  • var_kk442_100_r1.tar.bz2 - Variscite's VAR-SOM-MX6 SOM patch files

Unpack Freescale's Android Release Package

$ mkdir ~/var_kk_442_100
$ cd ~/var_kk_442_100
$ tar xvf ~/Downloads/android_kk4.4.2_1.0.0-ga_core_source.tar.gz
$ cd android_kk4.4.2_1.0.0-ga_core_source/code/
$ tar xvf kk4.4.2_1.0.0-ga.tar.gz

Download Google Android KK4.4.2

The Android source code is maintained in more than 100 different gits in the Android repository (
To get the Android source code from Google repo, follow the steps below:

$ cd ~/var_kk_442_100
$ mkdir kk_442_100_build
$ cd kk_442_100_build
$ mkdir ~/bin
$ curl > ~/bin/repo
$ chmod a+x ~/bin/repo
$ repo init -u -b android-4.4.2_r1
$ repo sync
The repo tool which was used by Variscite is available on FTP site.

Download Variscite's u-boot and Linux kernel

clone kk4.4.2_1.0.0-ga kernel source code from Variscite's open source git:

$ cd ~/var_kk_442_100/kk_442_100_build
$ git clone git:// kernel_imx
$ cd kernel_imx
$ git checkout -b kk4.4.2_1.0.0-ga-var01 remotes/origin/kk4.4.2_1.0.0-ga-var01

clone the U-Boot git repository from Varicite's open source git:

$ cd cd ~/var_kk_442_100/kk_442_100_build/bootable/bootloader
$ git clone git:// uboot-imx
$ cd uboot-imx
$ git checkout -b kk4.4.2_1.0.0-ga-var01 remotes/origin/kk4.4.2_1.0.0-ga-var01

Patching the AFS sources with Freescale i.MX6 support

The patch script ( requires some basic utilities like awk/sed.
Apply all Android patches by using the following steps:

$ cd ~/var_kk_442_100/kk_442_100_build
$ source ../android_kk4.4.2_1.0.0-ga_core_source/code/kk4.4.2_1.0.0-ga/
$ c_patch ../android_kk4.4.2_1.0.0-ga_core_source/code/kk4.4.2_1.0.0-ga imx_kk4.4.2_1.0.0-ga

Apply VAR-SOM-MX6 patches

After you setup your build machine,unpack Variscite's release Package:

$ cd ~/var_kk_442_100
$ tar xvf ~/Downloads/var_kk442_100_r1.tar.bz2
$ variscite/install

Build Android Images

Build the Android Filesystem

Change to Android top level directory.

$ cd ~/var_kk_442_100/kk_442_100_build
NOTE: edit and set -j4 to a suitable number. A good practice is to set it to number of threads of you build machine minus 1.
  • SD card build
$ ./ mx6q sdcard
  • UBIFS build
$ ./ mx6q ubifs

Build for 4GB NAND

Edit your located at device/variscite/var_som_mx6q. At the end comment out the UBIFS parameters and add: "
#Micron 4096MB MT29F32G08AFACAWP NAND
TARGET_MKUBIFS_ARGS := -m 4096 -e 516096 -c 7855 -x none
TARGET_UBIRAW_ARGS := -m 4096 -p 512KiB -s 4096 -O 4096 $(UBI_ROOT_INI)
Rebuild your ubi system and you will get new ubifs for 4GB nand flash. on the recovery sd card need to be updated with if [ `dmesg |grep MT29F32G08AFACAWP | wc -l` = 1 ] ; then # this is 4GB NAND (MT29F32G08AFACAWP) echo "4GB nand selected ..." ROOTFS_IMAGE=rootfs_4G_NAND.ubi.img ANDROID_SYSTEM=android_root_4G_NAND.img UBI_SUB_PAGE_SIZE=4096 UBI_VID_HDR_OFFSET=4096 fi


The Android can either be booted from MMC/SD device or UBIFS on NAND. 

Boot From MMC/SD Card

This section will guide you through the process of installing and boot VAR-SOM-MX6 from SD/MMC device.

Create bootable SD card

Variscite provides a script that can be used to partition the SD card and to install the required images on it.

  • Insert a micro SD into your Linux PC
  • Determine the block device name of your micro SD (for instance /dev/sdc)
  • Make sure all partitions of your micro SD are unmounted.
  • cd ~/var_kk_442_100/kk_442_100_build
  • sudo ./ /dev/sdX mx6q (replace /dev/sdX with your SD card block device)

Use the created SD card and:

  • Insert the SD card you just created into the MMC/SD slot on the custom board.
  • Press and hold the boot-select button and power-on the SOM.

Boot From NAND Flash

Flashing the U-Boot, boot image and Android UBI root file system into NAND can be done from target Linux shell.

The images  can be found at Android build machine under: "out/target/product/var_som_mx6".

Boot the target device using Variscite's pre-build NAND recovery SD image, then follow the instructions below:

Flashing U-Boot to NAND

We recommend using our nand-recovery utility to flash the Android. You can update the relevant files in /opt/recovery/Android and use it to flash your images.

# flash_eraseall /dev/mtd0 
# kobs-ng init <u-boot-mx6XXX.bin> --search_exponent=1 -v

Flashing the Boot Image to NAND

# flash_eraseall /dev/mtd3 
# nandwrite -p /dev/mtd3 <boot.img>

Flashing the Android UBI Root File-System to NAND

# flash_eraseall /dev/mtd5 2>/dev/null
# ubiformat /dev/mtd5 -f <android_root.img> -s 2048 -O 2048

Manual operations

Build boot.img

We use boot.img and booti as default commands to boot rather than the uramdisk and uImage.
You can use this command to generate boot.img under android environment:

$ cd ~/var_kk_442_100/kk_442_100_build
$ source build/
$ lunch var_som_mx6q-user
$ make bootimage

Toolchain setup for manual build kernel and u-boot

Setup the toolchain path to point to arm-eabi- tools in prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin

$ export ARCH=arm
$ export PATH=~/var_kk_442_100/kk_442_100_build/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin:$PATH
$ export CROSS_COMPILE=arm-eabi-

Manual build Bootloader 

Change directory to u-boot

$ cd ~/var_kk_442_100/kk_442_100_build/bootable/bootloader/uboot-imx 

Execute following commands:

$ make ARCH=arm distclean
$ make mx6q_var_som_android_config # VAR-SOM-MXQ/D, boot from MMC
$ make mx6solo_var_som_android_config # VAR-SOM-MXSolo, boot from MMC
$ make mx6dl_var_som_android_config # VAR-SOM-MXDL, boot from MMC
$ make mx6q_var_som_nand_android_config # VAR-SOM-MXQ/D, boot from NAND
$ make mx6solo_var_som_nand_android_config # VAR-SOM-MXSolo, boot from NAND
$ make mx6dl_var_som_nand_android_config # VAR-SOM-MXDL, boot from NAND
$ make -j4 

This command will generate the u-boot Image 'u-boot.bin'

Manual build Android Linux Kernel and modules

Change directory to kernel

$ cd ~/var_kk_442_100/kk_442_100_build/kernel_imx 

Execute following commands

$ make distclean
$ make var_som_mx6_android_defconfig
$ make -j4 uImage
$ make -j4 modules

This will generate uImage(kernel image) in kernel/arch/arm/boot folder

Flashing Android with Fastboot

  1. Connect a USB OTG cable from the target board OTG port to a you host machine USB HOST port.
  2. Power up the board and hit return to stop the boot
  3. type fastboot in the u-boot prompt.

On the target:

$ sudo `which fastboot` flash boot out/target/product/var_som_mx6q/boot.img
$ sudo `which fastboot` flash recovery out/target/product/var_som_mx6q/recovery.img
$ sudo `which fastboot` flash android_root out/target/product/var_som_mx6q/android_root.img
$ sudo `which fastboot` reboot

Display Options

Selecting the display type is done by setting the bootcmd with the required display type.

The bootcmd is embedded into boot.img. To set the bootargs edit the file '~/var_kk_442_100/kk_442_100_build/device/variscite/var_som_mx6/' as follows:

  • HDMI
BOARD_KERNEL_CMDLINE := console=ttymxc0,115200 init=/init video=mxcfb0:dev=hdmi,1920x1080M@60,if=RGB24,bpp=32 video=mxcfb1:off video=mxcfb2:off arm_freq=1000 fbmem=48M vmalloc=400M androidboot.console=ttymxc0 androidboot.hardware=freescale
  • Variscite's LCD (Capacitive and resistive)
BOARD_KERNEL_CMDLINE := console=ttymxc0,115200 init=/init video=mxcfb0:dev=ldb,bpp=32 video=mxcfb1:off video=mxcfb2:off arm_freq=1000 fbmem=24M vmalloc=400M androidboot.console=ttymxc0 androidboot.hardware=freescale

Android ADB Setup

Android Debug Bridge (adb) is a versatile tool that let you manage the state of the Android-powered device.

For more information about how to setup ADB adb, see TI ADB Setup page at

NOTE: When using adb over USB on Windows Machine, edit android_winusb.inf to match VAR-SOM-MX6 vendor and product ids, under [Google.NTx86] section add:

%SingleAdbInterface%        = USB_Install, USB\VID_18D1&PID_0D02
%CompositeAdbInterface%     = USB_Install, USB\VID_18D1&PID_0D02&MI_00