Marshmallow porting on Beaglebone black
steps:
1. Get Marshmallow AOSP source from Google
user:~$ curl commondatastorage.googleapis.com/.../repo > ~/bin/repo
user:~$ chmod a+x ~/bin/repo
user:~$ mkdir ~/aosp
user:~$ cd aosp
user:~$ repo init -u android.googlesource.com/.../manifest -b android-6.0.0_r5
user:~$ repo sync -c
2. Get device files for the BeagleBone Black
user:~$ cd ~/aosp/device
user:~$ mkdir ti
user:~$ cd ti
user:~$ git clone github.com/.../bbb-android-device-files.git beagleboneblack
user:~$ cd beagleboneblack
3. Get the Rowboat kernel configure and compile:
user:~$ cd ~/aosp
user:~$ git clone gitorious.org/.../kernel.git
user:~$ cd kernel
user:~$ git checkout rowboat-am335x-kernel-3.2
user:~$ patch -p1 < ../device/ti/beagleboneblack/kernel-patches/0001-Tweak-backlight-PWM-for- LCD4-Beaglebone-cape.patch
user:~$ patch -p1 < ../device/ti/beagleboneblack/kernel-patches/0002-Reboot-reason-flags-for- BBB.patch
user:~$ make ARCH=arm CROSS_COMPILE=arm-eabi- am335x_evm_android_defconfig
user:~$ make ARCH=arm CROSS_COMPILE=arm-eabi- -j4 uImage
user:~$ croot
4. Get U-Boot configure and compile:
user:~$ cd ~/aosp
user:~$ git clone github.com/.../u-boot
user:~$ cd u-boot
user:~$ make CROSS_COMPILE=arm-eabi- am335x_evm_config
user:~$ make CROSS_COMPILE=arm-eabi-
5. Build AOSP:
user:~$ . build/envsetup.sh
user:~$ lunch
- setect your device
user:~$ make -j8
6. Put the images on micro SD card:
You need a micro SD card of at least 2 GiB capacity. Insert your SD card into
your SD card reader. It will appear as either `/dev/sd?` Or as `/dev/mmcblk?`.
Use the following script to format and copy the images
user:~$ croot
user:~$ device/ti/beagleboneblack/write_sdcard.sh
Issues and Modifications:
This build has been tested on a BBB. Here are some issues that I am aware of:
The screen flickers whenever it is updated
The Linux 3.2 kernel is unreliable if built with the gcc 4.8 toolchain that comes with AOSP 6.0
I used gcc 4.7 toolchain
1. init: could not import file '/init.unknown.rc' from '/init.rc'
sol: It has to be our device file init.am335xevm.rc
For that we need to modify the BoardConfig.mk file in device/ti/beagleboneblack :
BOARD_KERNEL_CMDLINE := console=ttyO0,115200n8 androidboot.console=ttyO0 rootwait ro qemu=1 qemu.gles=0
I modified the above line as below
BOARD_KERNEL_CMDLINE := console=ttyO0,115200n8 androidboot.console=ttyO0 androidboot.hardware=am335xevm rootwait ro qemu=1 qemu.gles=0
2. init: Service 'sdcard' (pid 124) exited with status 1
init: Service 'sdcard' (pid 124) killing any children in process group
sol: I tried a lot on modifing init.rc file related to sdcard but it doesn't worked. Then i came to know that some modifications has to be done on beaglebone black device files which i have downloaded. I modified the two file fstab.am335xevm-sd & init.am335xevm.rc. Its worked!
The modifications are as follows:
-
device/ti/beagleboneblack/fstab.am335xevm-sd
Add the following line at the end of the above file
/devices/*/xhci-hcd.0.auto/usb* auto auto defaults voldmanaged=usb:auto
-
device/ti/beagleboneblack/ init.am335xevm.rc
Remove the following lines:
on init
mkdir /mnt/shell/emulated 0700 shell shell
mkdir /storage/emulated 0555 root root
export EXTERNAL_STORAGE /storage/emulated/legacy
export EMULATED_STORAGE_SOURCE /mnt/shell/emulated
export EMULATED_STORAGE_TARGET /storage/emulated
symlink /storage/emulated/legacy /sdcard
symlink /storage/emulated/legacy /mnt/sdcard
symlink /storage/emulated/legacy /storage/sdcard0
symlink /mnt/shell/emulated/0 /storage/emulated/legacy
on post-fs-data
mkdir /data/media 0770 media_rw media_rw
on fs
# virtual sdcard daemon running as media_rw (1023)
service sdcard /system/bin/sdcard /data/media /mnt/shell/emulated 1023 1023
class late_start
Add the following lines:
on init
# Load persistent dm-verity state
verity_load_state
# Support legacy paths
symlink /sdcard /mnt/sdcard
symlink /sdcard /storage/sdcard0
compile the AOSP source: ~/aosp$ make -j8
Put the images on micro SD card: ~/aosp$ device/ti/beagleboneblack/write_sdcard.sh
Thank You!!!
