Android Image content using DragonFace (and ImgRepacker, a bit)

ChrisP

I took some time to identify the way DragonFace is exporting various data from an android image and to figure how it can be used to go deeper in android image tweaking.
The main data source for partition structure is the file sysconfig.lhs exported in temp file during image loading by DragonFace.
File size found in sysconfig.lhs are number of blocks of 512 bytes.

I tried to see how to change the default kernel but for now I do not get yet how to manage the u-boot and just get a sdcard freezing during boot (just after the A20 image).
This is a summary of the various partition present in a 4.2 image, what is exported in temp folder, for some of them where the files are exported in DragonFace subfolders, and what proved or potential action can be done to tweak the Android image.

It could be usefull for some people I hope. Please feel free to comment/extend/correct anything

The Android 4.2 structure is then this one:

id	dev/ block/*	Size	Name	Target fs mount point	file	Type	Description	temp File exported by Dragon Face	Folder exported by DragonFace	Modification possible in DragonFace
	mbr	8MiB						mbr.lhs
0	nanda	16MiB	bootloader		bootloader .fex	vfat	Files to assist the bootloader. Think battery status images etc. also  u-boot.bin, script.bin and .ini lives here	bootloader .lhs	DF/fsop/bootfs ??? File DF/fsop/bootfs.ini let think that  but report a size of 128MiB	To be defined
1	nandb	16MiB	env		env.fex	raw	Enviroment to assist u-boot.			To be defined. Good candidate to redefine MAC address once proper edition method will be identified
2	nandc	32MiB	boot		boot.fex	raw	Holds the kernel (and its ramdisk) in ANDROID mkbootimg form	bootimg .lhs	DF/cpfop/bootfs + ramdisk in DF/cpfop/bootfs/skel	Kernel can be pushed in DragonFace/cpfop/bootfs but due to apparent  privilege issue, additionnal actions are needed:   1 - Duplicate DragonFace/cpfop/bootfs to DragonFace/cpfop/rootfs   2 - execute DragonFace/cpfop/pack_boot.bat   3 - rename DragonFace/cpfop/bootfsnew.fex to DragonFace/cpfop/bootfs/boot.fex
3	nandd	0.5GiB	system	/system	system.fex	ext4	Android's /system partition	system.lhs + working file .tmp	DF/fsop/system	Simple file copy in DragonFace/fsop/system
4	nande	1GiB	data	/data		ext4	Android /data partition			To be defined
5	nandf	16MiB	misc			raw	Partition used to pass data amongst various stages of the boot chain  (e.g. boot into recovery mode, fastboot etc)			To be defined
6	nandg	32MiB	recovery		recovery .fex	raw	Android's recovery partition	recovery .lhs	DF/cpfop/recovery + ramdisk in DF/cpfop/recovery/skel	Kernel can be pushed in DragonFace/cpfop/recoveryfs
7	nandh	32MiB	cache	/cache		ext4	Mounted as /cache and appear to contain backup information			To be defined
8	nandi	16MiB	private	/mnt/private		vfat	Mounted as /mnt/private			To be defined
9	nandj	256MiB	databk			raw	data image Backup			To be defined
10	nandk	768 MiB	sysrecovery		sysrecovery .fex	vfat ??	system image backup, disactivated in sysconfig.lhs			To be defined
11	nandl	N/A	UDISK	/mnt/sdcard + /mnt/secure /asec	diskfs.fex	vfat	Mounted by vold as /mnt/sdcard and /mnt/secure/asec			Apparently  no source file are needed. Is created on first image boot to take all remaining room available on sdcard. Investigation could be nice to check if this partition or datablk could be a way to offer default configuration for applications, like xbmc

The Android 4.4 structure is a little bit different:

id	dev/ block/*	Size	Name	Target fs mount  point	file	Type	Description	temp File exported by DragonFace	Folder exported  by DragonFace	Modification  possible in DragonFace
	mbr	8MiB						mbr.lhs
0	nanda	16MiB	bootloader		bootloader .fex	vfat	Files to assist the bootloader. Think  battery status images etc. also u-boot.bin, script.bin and .ini lives here	bootloader .lhs	DF/fsop/bootfs  ??? File DF/fsop/bootfs.ini let think that but report a size of  128MiB	To  be defined
1	nandb	16MiB	env		env.fex	raw	Enviroment to assist u-boot.			To be defined. Good candidate to redefine MAC address once proper edition method will be identified
2	nandc	16MiB	boot		boot.fex	raw	Holds the kernel (and its ramdisk) in  ANDROID mkbootimg form	bootimg.lhs	DF/cpfop/bootfs  + ramdisk in DF/cpfop/bootfs/skel	Kernel  can be pushed in DragonFace/cpfop/bootfs but due to apparent privilege issue,  additionnal actions are needed:     1 - Duplicate DragonFace/cpfop/bootfs to DragonFace/cpfop/rootfs     2 - execute DragonFace/cpfop/pack_boot.bat     3 - rename DragonFace/cpfop/bootfsnew.fex to  DragonFace/cpfop/bootfs/boot.fex
3	nandd	736MiB	system	/system	system.fex	ext4	Android's /system partition	system.lhs  + working file .tmp	DF/fsop/system	Simple  file copy in DragonFace/fsop/system
4	nande	640GiB	data	/data		ext4	Android /data partition			To  be defined
5	nandf	16MiB	misc			raw	Partition used to pass data amongst  various stages of the boot chain (e.g. boot into recovery mode, fastboot etc)			To  be defined
6	nandg	32MiB	recovery		recovery .fex	raw	Android's recovery partition	recovery .lhs	DF/cpfop/recovery  + ramdisk in DF/cpfop/recovery/skel	Kernel  can be pushed in DragonFace/cpfop/recoveryfs
7	nandh	640GiB	cache	/cache		ext4	Mounted as /cache and appear to contain  backup information			To  be defined
8	nandi	256MiB	databk			raw	data  image Backup			To  be defined
9	nandj	16MiB	private	/mnt/private		vfat	Mounted as /mnt/private			To  be defined
10	nandk	N/A	UDISK	/mnt/sdcard  + /mnt/secure /asec	diskfs.fex	vfat	Mounted by vold as /mnt/sdcard and /mnt/secure/asec			Apparently  no source file are needed. Is created on first image boot to take all remaining room available on sdcard. Investigation could be nice to check if this partition or datablk could be a way to offer default configuration for applications, like xbmc

   

ChrisP

For reference, I made a file mapping between what is accessible from DragonFace and what is available from imgRepacker from Redscorpio ( http://forum.xda-developers.com/showthread.php?t=1753473 )

RedScorpio  ImgRepacker dump files				Dragonface  temp folder files
Size	FileName	Content	Nature	Size	Filename
		Animated boot logo (expanded)		<DIR>	bootanimation
<DIR>	_iso
470548852	system.fex	/System	ext4 sparse filesystem	470548852	system.lhs
		/System temporary file	ext4 sparse filesystem	470548852	~ex3721.tmp
11102208	recovery.fex	Recovery		11102208	recovery.lhs
10584064	boot.fex	Kernel + Ramdisk (boot Android)		10584064	bootimg.lhs
5018624	bootloader.fex	Files to assist the bootloader.  Think battery status images etc. also u-boot.bin, script.bin and .ini lives  here		5018624	bootloader.lhs
		Animated boot logo (compressed)		3686400	logo.lhs
655360	u-boot.fex	Uboot (Boot1)		655360	boot1.lhs
				177288	bootlogo.lhs
132096	usbtool.fex	dll file
131072	env.fex	Enviroment to assist u-boot.
81920	cardtool.fex	dll file
65536	sunxi_mbr.fex	mbr		65536	mbr.lhs
60676	sys_config.fex	A20 PAD file (equivalent build.prop ??)		60676	sysconfig1.lhs
24576	boot0_nand.fex	Initial bootloader for Nand (Boot0)		24576	boot0.lhs
24576	boot0_sdcard.fex	Initial bootloader for sdcard (Boot0)		24576	cardboot0.lhs
16384	dlinfo.fex	SD Partition table ?		16384	dlinfo.lhs
7552	fes1.fex	(ram test, exe)		7552	fes1.lhs
3561	sys_partition.fex	PhoenixCard Partition schema		3561	sysconfig.lhs
2585	image.cfg	Fex filelist
1770	cardscript.fex	Card Script config file
512	diskfs.fex	Empty diskfs (zeroed)
512	split_xxxx.fex	guid list ?		512	DF\fsop\bootfs\magic.bin
4	Vboot.fex	Verification file, regenerated  during rebuild
4	Vbootloader.fex	Verification file, regenerated  during rebuild
4	Venv.fex	Verification file, regenerated  during rebuild
4	Vrecovery.fex	Verification file, regenerated  during rebuild
4	Vsystem.fex	Verification file, regenerated  during rebuild

afcajax

Keep up the good work! Based on this thread: http://zeustoolkit.moonfruit.com/building-livesuit-img/4583660804, i found that CPFOP\bootfs\skel\init.sun7i.rc may also be an interesing file

mattrix

I have tried modifying CPFOP\bootfs\skel\init.sun7i.rc but the changes are ignored.
I think DragonFace is just showing this \skel\ folder but doesn't actually re-pack it?

Did you find this?

mattrix

This is interesting:
http://forum.xda-developers.com/showthread.php?t=2318587

"u can use the simg2img binary to make the system.fex file to a mountable image by using [simg2img <system.fex system.img>]
now mount it...make a directory called system, type these commands in the shell , [sudo mount -o loop system.img system ] this will mount the system.img inside the folder. now to make life simpler type [sudo nautilus] (on ubuntu) n start the file manager with super user access. n navigate to the system folder. now u can change files,delete unwanted stuff etc. after ur done with it pack the system directory using the make_ext4fs binary,type [ make_ext4fs -s -l 500M -a system {location of the system directory} <filename.fex> ] u will get ur system.fex file which u can pack in a livesuit image and flash"

ChrisP

I had some issue with the bootfs repackaging. I had to launch the pack_boot.bat script in CPFOP after manually copying bootfs to rootfs folder. Try to open a cmd, go to DF/CPFOP folder and run manualy the pack_boot.bat script. Remove the first command of the script (echo off) to check what it's doing.

Regarding the sim2img, it's exactly equivalent to the way DragonFace export system.lhs to fsop/system and back to system.lhs. I tried it when I explored the imgrepacker way of unpacking the img file, and it works well too.

mattrix

After you used sim2img, what did you use in Windows to then extract the ext4 image?
I couldn't find any command line programs to do it (automate)

ChrisP

On Windows, I only use DrangonFace to extract system content. But I believe it should be possible using linux-equivalent commands from cygwin.

Adromir

I havent found a convenient way too yet. What i am able to do is to mount the image as a DVD-Rom. But you need to have a ext driver installed to be able to read the Files on it, like http://www.ext2fsd.com/ .

Or using the ext4 unpacker (http://sourceforge.net/projects/androidicsjbext/?source=directory) is a way. On its Scourceforge page they say it has a cli mode, which would be what i need, but I havent been able to make it work yet.

I found a couple of Linux Libraries for working with the Images (like simg2img, make_4extfs) ported to windows but I havent tried them out yet. If they work, maybe its possible to just port the other tools too (like over cygwin or with mingwin)

dlanor

Just remember that after copying files to a Windows environment for modification, and then copying the results back to the Android partitions, all their Linux-type access permission flags may be messed up. For some system files it may be important to restore those flags to their original values, in order for the system to work properly. When we do this through DragonFace, it carries the responsibility of restoring everything properly, but when using other methods we must ensure this ourselves...

The same also applies when attempting to add new scripts or drivers to the system, as it's important to ensure that the runtime Android system regards those files as valid and executable. So for such cases it's best to set the permission flags the same as those of other similar scripts and drivers already in the system.

Best regards: dlanor