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Writable /system for Rk29xx(T760/P71 et.)

60K views 85 replies 35 participants last post by  thenenea 
#1 · (Edited by Moderator)
Hi,All,

It works!! I did it!!

Just flash my boot.img into you T760 or P71 , the /system will FULL writable!!

At this time , pls download from Rk29xx's Writeable System V4

If you have any question , free to ask.

Notice :
1. Atfer flash , and reboot , you must wait at least 5 min !! Just take a rest !!
2. ONLY Boot.img need to be flash !!
3. If it work , ALL your datas will keep.
4. It is FULL rooted system ,and writeable system, you can edit any file in /system and /data !!

Boot.img for T760 https://docs.google.com/leaf?id=0B8hUXYDeoy_hYjdjNzYwN2UtMTk5Ny00MDI2LWI2OTctNGE0NzY1Njc5MGI2&hl=zh_CN
Tools v4.1 : https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B8hUXYDeoy_hOWIwZjgzNmEtZTUyZi00OGY4LWE0NjUtMDc2ZTJjMjc1MGE2&hl=zh_CN
 
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#10 · (Edited by Moderator)
As far as I know , Cube U9GT's /system is writeable!! But don't use official rom!!
Use this http://www.yuandaocn.com/down/N%E7%B3%BB%E5%88%97/N10/
because yuandao and Cube use the some hardware, Yuandao's official rom , embedded aufs module .

I will check U8GT later

About "remove system apps using your rk29xx image tool":
1. first unpack the image
2. check folder /system/app/ , all app are in there, remove anything as you want
3. repack the image
 
#5 ·
Thanks Wendal for the update, been following the update from teclast forum.

What is the difference from v3 posted earlier? I am using v3, the earlier boot.img was like 206kb in size.


This tested on 2.08, not too sure if boot.img from 2.08 can work with earlier firmware. Well I think you could try it, if there is any problem just use restore with latest flash tools using latest firmware should reset everything to pre-writable system.
 
#8 ·
This is the change history:
V1.0
system writeable , but not rooted system -- a bat file ,adb , modified boot.img ,and upgrade tool

V2.0
just some words change

V3.0
system writeable , rooted system -- a bat file ,adb , modified boot.img , and upgrade tool

V4
system writeable , rooted system -- modified boot.img , and upgrade tool

Diff V4 to V3
1. Just flash a modified boot.img into you T760 , it will work . without any bat file , adb push , etc..
2. If you clean all data (use fatory reset), V4 can work , But V3 will fail to power on .

Why V4 can do this?
Because I found a smart way to do :
1. mount system partition to /sysro
2. add a new service to call /init.sh
3. In init.sh
#!/busybox sh

if [ ! -e /data/sysrw/TAG ]; then
/busybox mkdir /data/sysrw
/busybox cp -r /sysro/* /data/sysrw/
/busybox touch /data/sysrw/TAG
/busybox cp /su /data/sysrw/bin/
reboot
fi
############################
As you see , I will check file /data/sysrw/TAG , if it is exist, It means isn't first boot
then , if it is first-boot, cp all files in /sysro/ to /data/sysrw/ ,and then root -- this setp will take 5 min !!

So , After you flash V4 boot.img , and power on the T760 , it will check and cp the files

in init.rc , I change the mount cmdline of data partition , so the system is FULL rooted.
BTW, have no more need of Superuser.apk

So, V4 is best version for you , by now.

about compatibility
2.0.8 and 2.0.7 is test by me , and some user report that 2.0.3 work perfect
 
#12 ·
Great work! Very nice and clean method indeed.
Thanks again!

I wonder if there is any tools to unpack recovery.img at this moment? this shows promise as we could do update of /system via recovery(maybe using a clockwork recovery mod?) and other like boot.img or kernel.img via rockchip tools.
 
#13 · (Edited by Moderator)
As far as I know , Cube U9GT's /system is writeable!! But don't use official rom!! Use this http://www.yuandaocn...B%E5%88%97/N10/ because yuandao and Cube use the some hardware, Yuandao's official rom , embedded aufs module . I will check U8GT later.

About "remove system apps using your rk29xx image tool": 1. first unpack the image 2. check folder /system/app/ , all app are in there, remove anything as you want 3. repack the image.
Thank you Wendal for your hard work! I'll take a chance and order the U8GT.
 
#14 ·
WARNING, Some user report : Upgrade from V3 to V4.1, T760 will keep reboot!!

Before you upgrade from V3 to V4.1, create a file name /data/sysrw/TAG first!!

Sorry!!

=================================================================================

Yes , there is a tools can unpack/repack recovery.img :
rk29打包解包工具ultra1.7.rar
This is a tool dev by a team call "RK28 Team"

But I am not sure that modify recovery.img will help.
 
#20 · (Edited by Moderator)
Hi All and Wendal!
I only have week T760 with such versions
ver Android 2.3.1
Linux 2.6.32#ver2.7@20110611
build v2.02_20110613

What to receive root access to me it would be possible to use version 4.2 at once
Or it is necessary to make any additional actions?
Can replace at first with version 2.0.3 or 2.0.8?
 
#21 · (Edited by Moderator)
Hello Wendal, and sorry for my English I'm Italian.
Congratulations for your work, I read what you've done so far and it is exceptional.
I ask your help to get write permissions to the folder system on my tablet.
The model is Mediacom 810c chip rk2918.
It is already root with your tool, but not have write permission.
Mediacom 810c has very similar features but has an 8-inch screen and 800 x 600 resolution.
I tried to use your boot.img it did not work.
I really hope you decide to help me.
I have attach the boot.img
This is the link to download the complete roms: http://www.megaupload.com/?d=V50CTOAD
Have a nice day
Pistoneone

View attachment boot.zip
 

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#23 · (Edited by Moderator)
Hi Wendal,

please can you change the Boot.img for the Odys Loox... look atachment
i try to use your tools but the are all in chinese and i cant read the Filenames and also the .BAT has no english words. with cryptet signs my system will not work


Big Thx

Edit:
i unpack the Boot.img from my odys and i unpack your boot.img 4.2
Then i delete the system folder
copy busybox, init.sh init.rc and filelist from your boot.im to mine.
repack all the files and flash the boot.img

they will reboot and reboot and reboot.
i create a folder /data/sysrw on my SDCARD.. the same problem
 

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#24 ·
Hi Wendal,

There is any possibility a chinese device call crespo, with cranfs file type system, become free for mount /system as s-off to modify that folder? I need to install chain fire in my tablet but I can't because there is not space available to do that and I can't delete nothing. Thank you my friend!
 
#26 ·
Wendal -

Would you be able to detail the specific changes made to your boot.img (v4.2) as compared to the retail boot.img that came with the T760? I would like to replicate your efforts on the Efun Nextpad Premium 8 (Next8P), and I might be able to sort it out, but some guidance would help.

My initial plan is to:

use rkdump to dump the device update.img
(there is no firmware download available, so this seems to be a viable alternative)

extract boot.img from update.img
extract boot.img contents
modify contents (** guidance needed **)
repackage boot.img
repackage update.img
flash device

Thanks in advance!
 
#29 · (Edited by Moderator)
I provide a better way:

1. a new loader, I will attach it. modify package-file
bootloader RK29xxLoader(L)_V1.63.bin
to
bootloader RK29xxLoader(L)_V2.06.bin

and replace RK29xxLoader(L).bin with RK29xxLoader(L)_V2.06.bin
and put RK29xxLoader(L)_V2.06.bin into Temp

2. unpack your boot.img , open init.rc found
mount cramfs mtd@system /system ro
change to
mount ext3 mtd@system /system wait rw

3. convert you system.img to ext3 format (in linux ):
dd if=/dev/zero out=/tmp/system.img bs=1024 count=200000
/sbin/mkfs.ext3 /tmp/system.img
mkdir /tmp/system
mount -t ext3 -o loop /tmp/system.img /tmp/system
cramfsck -x /tmp/system system.old.img
umount /tmp/system

then pack the rom , flash it
 

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#30 ·
Hi wendal, first of all thanks for all your help to the comunity and your great tools

I have Arnova 10 G2 tablet (RK2918 based - GC800 GPU) and want to create a custom ROM.
I followed your guide in last post but I wasn't successfull


I received one warning and one error during the proccess:
Code:
root@ubuntu:~# /sbin/mkfs.ext3 /tmp/system.img<br />
mke2fs 1.40.8 (13-Mar-2008)<br />
/tmp/system.img is not a block special device.<br />
Proceed anyway? (y,n) y<br />
Filesystem label=<br />
OS type: Linux<br />
Block size=1024 (log=0)<br />
Fragment size=1024 (log=0)<br />
20080 inodes, 80016 blocks<br />
4000 blocks (5.00%) reserved for the super user<br />
First data block=1<br />
Maximum filesystem blocks=67371008<br />
10 block groups<br />
8192 blocks per group, 8192 fragments per group<br />
2008 inodes per group<br />
Superblock backups stored on blocks: <br />
	8193, 24577, 40961, 57345, 73729<br />
<br />
Writing inode tables: done                            <br />
Creating journal (4096 blocks): done<br />
Writing superblocks and filesystem accounting information: done<br />
<br />
This filesystem will be automatically checked every 31 mounts or<br />
180 days, whichever comes first.  Use tune2fs -c or -i to override.<br />
<br />
After I hit y, it seems that it finnished successfully, but file size didn't change even one bit :/ Strange?

And now the error:
Code:
root@ubuntu:~# cramfsck -x /tmp/system /tmp/system.img<br />
cramfsck: superblock magic not found
Could you please advice what I'm doing wrong or what I'm missing?

Also mount command doesn't seem to do anything, directory /system is empty after mount (only lost+found subdir is created)

Thank in advance


P.S. if interested, latest official FW for ARNOVA can be found here
 
#31 · (Edited by Moderator)
Hi Wendal,

To start with, thank you very much for the effort you make for helping we all (plase forgive me if my english is not good enough, I am spanish).

I would like to ask you something, I bought a BQ Kepler (it is a tablet) two months ago, more or less, and it uses the RK29xx chip, using the rk29xximagetools I was able to unpack its original firmware and extract all the files, even I was able to root it but the problem is that, once I have deleted from SYSTEM > APP the apps I do not want and reflash the kepler with the modified rom, the system folder becomes read only (cramfs, or something like that).
I have read all the posts from the first one and, if I am not wrong, the solution would be to flash the kepler with the boot.img that can be found in rk2918system v4.2, is it correct?, If not, what could I do?.

I have attached its original boot.img just in case You would like to have a look. View attachment boot.zip
A copy of the tablet´s firmware can be found here: http://www.zshare.net/download/966431840917b46a/

Once more, thank you very much for doing your best.

Kindest regads

Angel Cervera
 

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