VAR-SOM-MX6 Android GS

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Revision as of 20:57, 22 January 2014 by Oren (talk | contribs)
VAR-SOM-MX6 Android-JB-4.2.2 110 r2 DevelopersGuide

1 Introduction

This is the second release for VAR-SOM-MX6 Android-JB-4.2.2 110. It includes full Buletooth support on all platforms. Camera support added to the DL and Solo platforms.

The defintion is splited into 3 platforms : Q, DL and Solo to enable better tuning  for som based parameters.

2 Overview

The objective of this document is to guide Android developers to get access to Android JellyBean release sources for VAR-SOM-MX6, setting up host environment for compilation and deployment.

This document contains instructions to:

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

2.1 Document Reference

This release is based on Freescale Rev jb4.2.2_1.1.0-GA, 07/2013 release. Please download and read the documents android_jb4.2.2_1.1.0-ga_doc.tar.gz.

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

3 Supported hardware and features



Board support



i.MX6 Quad

i.MX6 Dual
i.MX6 Dual lite
i.MX6 Solo

Software platform

Freescale Android-JB-4.2.2 110

Nand Recovery NAND-recovery SD V21_1 - can be downloaded from FTP
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 :

Variscite Android release for Freescale i.MX6 version Android-JB-4.2.2 110.

4 Hardware Requirements

VAR-SOM-MX6 evaluation kit.

4.1 Host (PC) setup requirements

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

We recommend you to have a Linux "Ubuntu 12.04 64bit LTS" Host machine.


This DevKit Release was built with 64-bit Ubuntu 12.04. We highly recomend to use this version as your build system.
The host installation would need few more Android specific dependencies, these can be installed dynamically over network using below commands.

4.1.2 For 64-bit Ubuntu 12.04

The complete Android host requirments:

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

$ 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/

4.1.3 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 to the system which JDK should be used.

Java 6: for Gingerbread and newer

$ sudo add-apt-repository "deb lucid partner"
$ sudo apt-get update
$ sudo apt-get install sun-java6-jdk

4.1.4 Additional packages

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

$ sudo apt-get install uuid uuid-dev
$ sudo apt-get install zlib1g-dev liblz-dev
$ sudo apt-get install liblzo2-2 liblzo2-dev
The Hard Disk should have at least 30 GigaBytes of free space to complete the building of sources.
Please refer to the AOSP documentation for latest information and instructions for setting up other Ubuntu versions

5 Getting Variscite Android installer

Variscite provides an Android Release Package with a Variscte installer to support VAR-SOM-MX6. The Linux kernel and U-Boot are avialble through GITHUB.

The Android JB installer Package for the VAR-SOM-MX6 can be obtained from Variscite's FTP, under:

6 Build Android for i.MX6

6.1 Download Android Source Code (AFS/Kernel/U-Boot)

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

$ mkdir ~/var_jb_422_110
$ cd ~/var_jb_422_110
$ tar xvf ~/Downloads/android_jb4.2.2_1.1.0-ga.tar.gz 
$ tar xvf android_jb4.2.2_1.1.0-ga_source.tar.gz
$ rm android_jb4.2.2_1.1.0-ga_source.tar.gz
$ rm android_jb4.2.2_1.1.0-ga_tool.tar.gz 

Unzipp Variscite's Android package to ~/var_jb_422_110/android_jb4.2.2_1.1.0-ga_source/.

$ cd ~/var_jb_422_110
$ mkdir jb_422_110_build
$ cd jb_422_110_build
$ curl > ~/repo
$ chmod a+x ~/repo
$ ~/repo init -u -b android-4.2.2_r1
$ ~/repo sync # this command loads most needed repos. Therefore, it can take a while to load.
we uploaded as a reference the repo we used.

clone jb4.2.2_1.1.0-ga kernel source code from Variscite's open source git:

$ cd ~/var_jb_422_110/jb_422_110_build
$ git clone git:// kernel_imx
$ cd kernel_imx
$ git checkout -b jb4.2.2_1.1.0-ga-var13 remotes/origin/jb4.2.2_1.1.0-ga-var13

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

$ cd ~/var_jb_422_110/jb_422_110_build/bootable/bootloader
$ git clone git:// uboot-imx
$ cd uboot-imx
$ git checkout -b jb4.2.2_1.1.0-ga.var13 remotes/origin/jb4.2.2_1.1.0-ga.var13

6.2 Patching the source code

The patch script ( requires some basic utilities like awk/sed.
Apply all patches by the following steps:
Assuming you have unzipped i.MX Android release package to ~/var_jb_422_110/android_jb4.2.2_1.1.0-ga_source.

$ cd ~/var_jb_422_110/jb_422_110_build
$ cd ../android_jb4.2.2_1.1.0-ga_source/code/
$ tar xvf jb4.2.2_1.1.0-ga.tar.gz 
$ cd -
$ source ../android_jb4.2.2_1.1.0-ga_source/code/jb4.2.2_1.1.0-ga/
$ help
Now you should see that the "c_patch" function is available
$ c_patch ../android_jb4.2.2_1.1.0-ga_source/code/jb4.2.2_1.1.0-ga imx_jb4.2.2_1.1.0-ga

Here "../android_jb4.2.2_1.1.0-ga_source/code/jb4.2.2_1.1.0-ga" is the location of the patches (i.e. directory created when you unzip release package)
"imx_jb4.2.2_1.1.0-ga" is the branch which will be created automatically for you to hold all patches (only in those existing Google gits).

If everything is OK, "c_patch" will generate the following output to indicate successful patch:
Success: Now you can build the Android code for FSL i.MX platform
The patch script ( requires some basic utilities like awk/sed. If they are not
available on your Linux computer, install them first.

7 Patch Vaiscite support for VAR-SOM-MX6

After you setup a Linux PC, unpack the Android Release Package using the following commands:

$ cd ~/var_jb_422_110/jb_422_110_build
$ tar xvf var_jb422_110_r2_v10.tar.bz2
$ variscite/install

8 Build Android Images

8.1 Build Android Filesystem

  • Change directory to Android top level directory.
$ cd ~/var_jb_422_110/jb_422_110_build
  • Execute following commands
$ source build/

Select one of based on your target platform:

$ lunch var_som_mx6q-user
$ lunch var_som_mx6dl-user
$ lunch var_som_mx6solo-user


$ make -j6

The above make will build the u-boot and Linux for Variscite SOM's. Re run it to build the Anderoid.

Comment: if you have an 8 core PC use -j9. This will speed up the build. A good practice will be to use the number of CPU,s threads + 2.

8.2 Generate UBI images

To generate UBI images to be installed on NAND flash type the following commands after you run the above make:

For Quad platform:

$ chmod 644 out/target/product/var_som_mx6q/system/build.prop
$ rm out/target/product/var_som_mx6q/userdata.img
$ make -j4 PRODUCT-var_som_mx6q-user BUILD_TARGET_FS=ubifs

For Dual Lite platform:

$ chmod 644 out/target/product/var_som_mx6dl/system/build.prop
$ rm out/target/product/var_som_mx6dl/userdata.img
$ make -j4 PRODUCT-var_som_mx6dl-user BUILD_TARGET_FS=ubifs

For Solo platform:

$ chmod 644 out/target/product/var_som_mx6solo/system/build.prop
$ rm out/target/product/var_som_mx6solo/userdata.img
$ make -j4 PRODUCT-var_som_mx6solo-user BUILD_TARGET_FS=ubifs
  • The above commands will build the Android file-system, kernel, related modules and U-Boot.
  • Android rootfs components (root and system directories) will be located in 'out/target/product/var_som_mx6'.
  • The UBI build must be run only after the first build.

8.3 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:

$ source build/
$ lunch var_som_mx6-user
$ make bootimage

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.

8.4 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 CROSS_COMPILE=~/var_jb_422_110/jb_422_110_build/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin/arm-eabi-

8.5 Manual build Bootloader 

Change directory to u-boot

$ cd ~/var_jb_422_110/jb_422_110_build/bootable/bootloader/uboot-imx 

Execute following commands:

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

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

8.6 Manual build Android Linux Kernel and modules

Change directory to kernel

$ cd ~/var_jb_422_110/jb_422_110_build/kernel_imx 

Execute following commands

$ make ARCH=arm distclean
$ make ARCH=arm var_som_mx6_android_defconfig
$ make ARCH=arm uImage
$ make ARCH=arm modules

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

9 Boot

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

9.1 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.

Please download from the FTP site.

If you buid an image for UBIFS you need to re run your build:

$ make clean
$ make -j6

Connect the SD-Card(2GB>) to the Linux machine, using a memory card reader to the Linux machine.

  • Note the name allocated for this device. Type "dmesg". The SD card name should show up near the end, usually something like "SDC" (/dev/sdc) or "SDD" (/dev/sdd) or "MMC" . replace "/dev/mmcblk0" with the right one.
  • Run the following command:

To create SD card for VAR-SOM-MX6Q device:

$ cd ~/var_jb_422_110/jb_422_110_build
$ sudo ./  /dev/mmcblk0 mx6q

To create SD card for VAR-SOM-MX6DL device:

$ cd ~/var_jb_422_110/jb_422_110_build
$ sudo ./ /dev/mmcblk0 mx6DL

To create SD card for VAR-SOM-MX6Solo device:

$ cd ~/var_jb_422_110/jb_422_110_build
$ sudo  ./ mx6solo

9.1.1 Boot Android from SD card

  • 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.

9.2 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:

9.2.1 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>

9.2.2 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

10 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 '~/imx-android-jb4.2.2_1.0.0-ga-var11/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

11 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

12 Testing

12.1 Audio

The default Android sound recorder application use a a very low sampling rate producing a poor sound.

Plug a Disk-On-Key FAT32 formated into the USB host port.

Plug an audio source (like a PC line out or smartphone line out) into the line in connector.

Plug speakers (like PC speakers) into the line out connector.

root@android:/ # tinycap /mnt/udisk/48b.wav -d 0 -b 24 -c 2 -r 48000 

Hit CTRL-C after couple of seconds or more.

root@android:/ # tinyplay /mnt/udisk/48b.wav  

12.2 USB OTG as a device

Test the OTG as a device using Android ADB tool.
On target:
Under devloper option enable ADB debugguing

On Host:

$ sudo out/host/linux-x86/bin/adb kill-server
$ sudo out/host/linux-x86/bin/adb start-server
$ sudo out/host/linux-x86/bin/adb devices
$ sudo out/host/linux-x86/bin/adb shell

12.3 USB OTG as a host

Use an external HUB. Plug into it a Disk-On-Key, mouse and keyboard.

Make sure with the Android GUI that they are functional.


Plug a mouse into all 3 ports and make sure it is working.

Use an external HUB. Plug into it a Disk-On-Key, mouse and keyboard.
Plug it into all 3 ports and make sure all 3 devices are functioning.

12.5 HDMI

Boot the system and press spacebar to get into u-boot.

Change enviroment setting with the folowing command

setenv bootargs console=ttymxc0,115200 androidboot.console=ttymxc0 init=/init video=mxcfb0:dev=hdmi,1920x1080M@60,bpp=32 video=mxcfb2:off arm_freq=1000 fbmem=28M vmalloc=400M androidboot.hardware=freescale caam mxc_hdmi.only_cea=1 mtdparts=setenv mtdpar gpmi-nand:16m(bootloader),16m(bootimg),32m(recovery),-(root) ubi.mtd=3 var_ts_type=ctw6120

Plug an HDMI TV or monitor to the HDMI port and boot the system by typing boot into u-boot.

You should see the Android on a full 1080p device.

12.6 External LVDS display

Boot the system and press spacebar to get into u-boot.
Change enviroment setting with the folowing command
For Quad, Dual and DualLite SOM's use:

setenv bootargs console=ttymxc0,115200 init=/init ldb=sin1 video=mxcfb0:dev=ldb,800x600M@60,bpp=32 video=mxcfb1:off video=mxcfb2:off arm_freq=1000 fbmem=24M vmalloc=400M androidboot.console=ttymxc0 androidboot.hardware=freescale mtdparts=gpmi-nand:16m(bootloader),16m(bootimg),32m(recovery),-(root) ubi.mtd=3

For Solo use:

setenv bootargs console=ttymxc0,115200 init=/init ldb=sin1 video=mxcfb0:dev=ldb,800x600M@60,bpp=32 video=mxcfb1:off video=mxcfb2:off arm_freq=1000 fbmem=24M vmalloc=400M androidboot.console=ttymxc0 androidboot.hardware=freescale gpumem=64M mtdparts=gpmi-nand:16m(bootloader),16m(bootimg),32m(recovery),-(root) ubi.mtd=3

12.7 Ethernet

Just plug a cable into the system

12.8 WIFI

Use the Android GUI to enable and connect to a WIFI AP.


Use the Android GUI to enable.

Test with file transfer to host PC, Bluetooth mouse and Bluetooth keyboard.

12.10 Camera

Use the Android GUI to activate and test the camer. You can take a picture and send it over Bluetooth to a PC host.

12.11 SATA

cat /proc/scsi/scsi
busybox fdisk -ul /dev/block/sda

In the above commands you will see SCSI status and device partition table.

If the device is FAT32 formated Android will auto mount it.

12.12 RTC (Real Time Clock)

Disable the auto clock sync from the Android GUI.

busybox date 2013.12.01-10:50
busybox hwclock --systohc

Also can set clock via GUI and check it later.

In any method power down the board and wait 5 minutes. After that power up the board and check the the clock is correct.