Starting with your Allwinner Image File
This guide is based on the experiences that our droid friends have shared with us.
This guide details how to deconstruct an existing allwinner android image, such as the default A31 image, and to build your own new flashable image.
This guide requires a native Windows installation, I’ve tried to do it from Ubuntu using a Windows VM and it didn’t work. This installation also requires a Linux install, either in a VM or a native install.
- IMG Repacker – for extracting and building the final image
- Stock firmware – as a starting base.
- Linux image tools – for extracting and building the partitions of the image.
- A text editor that supports Unix line endings, do not use Notepad. A fantastic text editor is Notepad++
Extracting and building the stock image (Windows)
a10_flash_kitchen_v1.zip and look inside the directory, you’ll see
packer_ics. packer_ics is for Android ICS, so that is the one you will be using.
packer_ics and you will notice a bunch of directories and a couple of .bat scripts. We will spend a lot of time in these directories.
Extract the stock firmware you downloaded earlier, and copy the .img file into this directory. Rename the file to
extract_image.bat script, and a command window will pop up while it is extracting.
The command window will output like the following, it will display Press any key to continue . . . when it is complete. Press a key to close the window.
Once the command window is closed, open the _extract directory and all of the extracted files will be there. The three following files are the ones we are interested in:
RFSFAT16_BOOT_00000000000.fex (the boot partition),
RFSFAT16_RECOVERY_0000000.fex (the recovery partition),
RFSFAT16_SYSTEM_000000000.fex (the system partition, ext4 sparse).
NOTE and WARNING (from a reader): Some systems may also have a
RFSFAT16_BOOTLOADER_00000.fex, which may also be required for your device to boot properly.
Extracting, modifying and building partitions (Linux)
Setting up Linux
First of all, I won’t go into detail about how to install and use Linux, as it is out of the scope of this guide. I will, however, go into great detail about the commands that have to be run, so it would be possible to follow the guide without deep Linux knowledge.
I would recommend installing an Ubuntu 12.04 64-bit VM using the free VirtualBox. Make sure you use the 64-bit version as some of the tools required are 64-bit. Also, you will need to install ia32-libs using
sudo apt-get install ia32-libs from the terminal.
In my case, I added my Windows drive in the shared folders settings before launching the VM, and set it to auto mount. I then added my user to the vboxsf group, allowing read and write access to these directories (/mount/share_name). To add your user to the vboxsf group, use
sudo usermod -aG vboxsf username from the terminal where username is the username of your user.
Once you’ve installed and booted into Ubuntu, you’ll see something like this:
First, click on the home folder icon on the left, and navigate to your Windows drive. My Windows drive was at
/media/sf_WINDOWS, which is accessible in the file manager via
File System ->
sf_WINDOWS. If you get a permissions error, either you haven’t added your user to the
vboxsf group, or if you have done that you might need to log off and back on.
Now browse to your
a10_flash_kitchen_v2/packer_ics/_extract directory, and locate the files
Copy these files, and create a directory in your Home and paste the files in there. I created a directory called
custom image. Be careful with having spaces in directory names, as the directory name will have to be quoted when we are in the terminal. Eg.
cd "custom image".
Rename the files as follows:
RFSFAT16_BOOT_00000000000.fex -> boot.img RFSFAT16_RECOVERY_0000000.fex -> recovery.img RFSFAT16_SYSTEM_000000000.fex -> system.fex
After renaming, your files should like like the following:
tools.tar.gz archive you downloaded earlier into the same directory.
To extract the tools, right click on the file and click Extract here.
This will extract the tools into a
Now we want to do some work in the terminal. Click the Dash home button on the left.
Type terminal to show the terminal application. Hit enter and the terminal will appear.
Execute the following commands, substituting “custom image” for the name of the directory you created in your home. Running
ls at the end will show the files we now have in the directory.
$ cd "custom image" $ tools/split_bootimg.pl boot.img $ ls
Now extract the ramdisk file into a ramdisk subdirectory.
$ mkdir ramdisk $ cd ramdisk $ gunzip -c ../boot.img-ramdisk.gz | cpio -i $ ls
You are now able to modify the files as needed. For example, the DroidMote developer added
insmod /system/vendor/modules/uinput.ko to the
init.sun4i.rc file to load uinput on boot.
Once you have finished modifying the file, we will rebuild the image. Run the following commands.
$ cd .. $ tools/mkbootfs ramdisk | gzip > ramdisk-new.gz $ tools/mkbootimg --base 0x40000000 --kernel boot.img-kernel --ramdisk ramdisk-new.gz --cmdline 'console=ttyS0,115200 rw init=/init loglevel=8' -o new-boot.img $ ls
This follows the same process as the boot partition. Execute the following commands to extract the image:
$ tools/split_bootimg.pl recovery.img $ rm -rf ramdisk $ mkdir ramdisk $ cd ramdisk $ gunzip -c ../recovery.img-ramdisk.gz | cpio -i $ ls
Modify files as needed, then rebuild the image with the following commands:
$ cd .. $ tools/mkbootfs ramdisk | gzip > ramdisk-new.gz $ tools/mkbootimg --base 0x40000000 --kernel recovery.img-kernel --ramdisk ramdisk-new.gz --cmdline 'console=ttyS0,115200 rw init=/init loglevel=8' -o new-recovery.img $ ls
The process for the system partition is different, because it is not bootable and because it is ext4 sparse, so it cannot be mounted straight away. Execute the following commands to convert and mount the image:
$ tools/simg2img system.fex system.img $ mkdir system $ sudo mount -o loop system.img system $ cd system $ ls
Here are the system files, modify as needed. Once you are done, execute the following commands to rebuild the system image:
$ cd ../tools $ sudo ./mkuserimg.sh -s ../system ../new-system.fex ext4 ../tmp 300M $ cd .. $ sudo umount system $ ls
Now switch back to the file browser and you will see many new files in your directory. The three files that you are interested in are
Copy these to your Windows drive to the directory
Building the new image (Windows)
Once the files are copied, jump back to Windows and rename the files as following:
new-boot.img -> root.fex new-recovery.img -> recovery.fex new-system.fex -> system.fex
Now we need to make some modifications to the image config file. Navigate to the
files directory and you should see
Open this file using your text editor that supports Unix line endings. Using Notepad will break this file. Locate the two lines that reference
VOEM as is highlighted below.
Comment these lines by adding a semicolon (;) to the start of each line. Do not make any other modifications. Save the file once you have made the change.
Go back to the
packer_ics root directory and find the
create_image.bat script. It will open a console while it is creating the new image.
Once the process is complete, you will see
Press any key to continue . . . and you will have a new image called
Use LiveSuit to flash this image to an MK802. If you brick the device and it doesn’t boot, just flash the stock firmware to bring the device back to life.