iMX6 OpenRex Ultra Android

Android is a mobile operating system (OS) based on the Linux kernel and currently developed by Google.

This document describes installation procedure for binary Freescale Android 7.1 image. Supported peripherals on iMX6 OpenRex SBC Ultra:

• HDMI/LVDS output
• USB flash as external storage
• SD card as external storage
• Video playback
• Audio playback
• WiFi
• Ethernet

Android 7.1

Install Prerequisites

sudo apt-get install uuid uuid-dev
sudo apt-get install zlib1g-dev liblz-dev
sudo apt-get install liblzo2-2 liblzo2-dev
sudo apt-get install lzop
sudo apt-get install git-core curl
sudo apt-get install u-boot-tools
sudo apt-get install mtd-utils
sudo apt-get install android-tools-fsutils
sudo apt-get install openjdk-8-jdk

Source code

Downloadable files needed during the building:

• Documentation for Android provided by NXP

• Source code with patches provided by NXP

• Voipac patches that add support for iMX6 OpenRex boards

Applying Voipac patches

tar xvzf android_N7.1.1_1.0.0_source_voipac.tar.gz -C ~/workdir/imx6/android/

cd ~/workdir/imx6/android/a711-rex/device/
tar xvzf ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/device_vpac-proprietary_voipac.tar.gz -C .

cd ~/workdir/imx6/android/a711-rex/device/fsl/
git apply ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/device_fsl_voipac.patch

cd ~/workdir/imx6/android/a711-rex/bootable/bootloader/uboot-imx
git apply ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/bootable_bootloader_uboot-imx_voipac.patch

cd ~/workdir/imx6/android/a711-rex/kernel_imx
git apply ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/kernel_imx_voipac.patch

cd ~/workdir/imx6/android/a711-rex/hardware/imx
git apply ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/hardware_imx_voipac.patch

cd ~/workdir/imx6/android/a711-rex/hardware/broadcom/wlan
git apply ~/workdir/imx6/android/android_N7.1.1_1.0.0_source_voipac/hardware_broadcom_wlan_voipac.patch

Build name options

• imx6tinyrex - iMX6 TinyRex Module Pro/Max/Max4G/Ultra
• imx6rex - iMX6 Rex Module Pro/Ultra
• imx6openrex - iMX6 OpenRex SBC Max/Max4G/Ultra

Build type options

• user - Production ready image, no debug
• userdebug - Provides image with root access and debug, similar to "user"
• eng - Development image with debug tools

Building commands

cd ~/workdir/imx6/android/a711-rex
source build/envsetup.sh

lunch imx6tinyrex-userdebug
make 2>&1 | tee build-log-imx6tr.txt

lunch imx6rex-userdebug
make 2>&1 | tee build-log-imx6r.txt

lunch imx6openrex-userdebug
make 2>&1 | tee build-log-imx6or.txt

Compiled files are stored in the ouput directory:

cd ~/workdir/imx6/android/a711-rexout/
ls -la out/target/product/

drwxrwxr-x  6 user user 4096 7 24 07:19 .
drwxrwxr-x  4 user user 4096 8 30  2017 ..
drwxrwxr-x 11 user user 4096 8 22 21:34 imx6openrex
drwxrwxr-x 11 user user 4096 7 28 20:19 imx6rex
drwxrwxr-x 11 user user 4096 6 18  2017 imx6tinyrex
drwxrwxr-x 11 user user 4096 5  1  2017 sabresd_6dq

Binary files

Official Voipac Android files can be found in downloads section.

Preparing SD card

mkdir -pv ~/workdir/imx6/android/bin/7_1/tinyrex
cd ~/workdir/imx6/android/bin/7_1/tinyrex
wget -r -nH -nd -np -R index.html* http://downloads.voipac.com/index.php?p=iMX6_OpenRex_SBC/software/android/Android_7_1/binaries
chmod a+x vpac-sdcard-partition.sh

SD card partition layout

This will be the final SD card partitioning layout at the end of installation procedure:

Partition type/index	Name	Start offset	Size	File system	Content
N/A	BOOT Loader	1 KB	1 MB	N/A	bootloader
Primary 1	Boot	8 MB	32 MB	boot.img format, kernel + ramdisk	boot.img
Primary 2	Recovery	Follow Boot	32 MB	boot.img format, kernel + ramdisk	recovery.img
Logic 5 (Extended 3)	SYSTEM	Follow Recovery	1536 MB	EXT4. Mount as /system	system.img (Android system files under /system/ dir)
Logic 6 (Extended 3)	CACHE	Follow SYSTEM	512 MB	EXT4. Mount as /cache	Android cache for image store of OTA
Logic 7 (Extended 3)	Device	Follow CACHE	8 MB	EXT4. Mount as /vender	To Store MAC address files
Logic 8 (Extended 3)	Misc	Follow Device	6 MB	N/A	For recovery store bootloader message, reserve
Logic 9 (Extended 3)	DATAFOOTER	Follow Misc	2 MB	N/A	For crypto footer of DATA partition encryption bootloader message, reserve
Primary 4	DATA	Follow Misc	Total - Other images	EXT4. Mount at /data	Application data storage for the system application and for internal media partition in /mnt/sdcard/ dir

Creating SD card

Based on the location where the SD card has been mounted alter and use one of these commands:

sudo ./vpac-sdcard-partition.sh -f imx6openrex ultra /dev/mmcblkX

or

sudo ./vpac-sdcard-partition.sh -f imx6openrex ultra /dev/sdX

Setup

Bootloader

Android bootloader is stored in SD card and directly executed. Linux bootloader stored in SPI flash must be configuration to chainload Android bootloader.

Chainloading SD card bootloader

setenv bootcmd "bmode esdhc2"
saveenv
reset

Setting HDMI video output

setenv bootargs "console=ttymxc0,115200 init=/init video=mxcfb0:dev=hdmi,if=RGB24,bpp=32 video=mxcfb1:off vmalloc=128M androidboot.console=ttymxc0 consoleblank=0 androidboot.hardware=freescale cma=320M"
saveenv

Setting LVDS video output

setenv bootargs "console=ttymxc0,115200 init=/init video=mxcfb0:dev=ldb,edt570,if=RGB666 video=mxcfb1:off vmalloc=128M androidboot.console=ttymxc0 consoleblank=0 androidboot.hardware=freescale cma=320M"
saveenv