Very basic guide to extract the initramfs from the zImage, as well as a dump of the initramfs inside I9100XEKDB firmware.
Q: Why? This is simple!
A: Might help someone out!
Linux Bash script follows (standard initramfs extract script) :
Code:
pos=`grep -F -a -b -m 1 --only-matching $'\x1F\x8B\x08' zImage | cut -f 1 -d :`
dd status=noxfer if=zImage bs=$pos skip=1 2>/dev/null| gunzip -q > kernel.img
start=`grep -F -a -b -m 1 --only-matching '070701' kernel.img | head -1 | cut -f 1 -d :`
dd status=noxfer if=kernel.img bs=$start skip=1 > initramfs.img 2>/dev/null
mkdir initramfshere
cd initramfshere
cpio -i --no-absolute-filenames < ../initramfs.img
ls -l
I9100XEKDB initramfs: http://www.sgscompilebox.dreamhosters.com/initramfs.tar.gz
Repacking should be easy as well, but I haven't tried to boot a kernel I have repacked myself yet. Since Chainfire has a root kernel posted, it should work without issue though -- and these are standard linux kernels after all.
Grab the kernel repacker from http://www.sgscompilebox.dreamhosters.com/repacker.tar.gz
Following bash script to use it:
Code:
end=`repacker/findcpio.pl kernel.img | cut -f 2`
(cd initramfshere/; find . | cpio --quiet -R 0:0 -H newc -o > ../newinitramfs.img)
gzip -f9c newinitramfs.img > newinitramfs.img.gz
repacker/kernel_repacker.sh zImage newinitramfs.img.gz
Might need some tweaking depending on your system, but this will hopefully get you started. You can use this to create your own root kernels as Chainfire has done, or modify as you want. Refer to the Q&A above!
Hi,
You can also find Samsung unmodified Galaxy S II initramfs on github, contributions welcome for missing ones:
https://github.com/GalaxySII/initramfs-galaxysii
Its repository collections is for every developer, and is not project/people specific: https://github.com/GalaxySII/
This is what Samsung should give us directly.
Related post, with reference Kernel source repository: http://forum.xda-developers.com/showthread.php?t=1054738
RyanZA said:
Very basic guide to extract the initramfs from the zImage, as well as a dump of the initramfs inside I9100XEKDB firmware.
Q: Why? This is simple!
A: Might help someone out!
Linux Bash script follows (standard initramfs extract script) :
Code:
pos=`grep -F -a -b -m 1 --only-matching $'\x1F\x8B\x08' zImage | cut -f 1 -d :`
dd status=noxfer if=zImage bs=$pos skip=1 2>/dev/null| gunzip -q > kernel.img
start=`grep -F -a -b -m 1 --only-matching '070701' kernel.img | head -1 | cut -f 1 -d :`
dd status=noxfer if=kernel.img bs=$start skip=1 > initramfs.img 2>/dev/null
mkdir initramfshere
cd initramfshere
cpio -i --no-absolute-filenames < ../initramfs.img
ls -l
I9100XEKDB initramfs: http://www.sgscompilebox.dreamhosters.com/initramfs.tar.gz
Repacking should be easy as well, but I haven't tried to boot a kernel I have repacked myself yet. Since Chainfire has a root kernel posted, it should work without issue though -- and these are standard linux kernels after all.
Grab the kernel repacker from http://www.sgscompilebox.dreamhosters.com/repacker.tar.gz
Following bash script to use it:
Code:
end=`repacker/findcpio.pl kernel.img | cut -f 2`
(cd initramfshere/; find . | cpio --quiet -R 0:0 -H newc -o > ../newinitramfs.img)
gzip -f9c newinitramfs.img > newinitramfs.img.gz
repacker/kernel_repacker.sh zImage newinitramfs.img.gz
Might need some tweaking depending on your system, but this will hopefully get you started. You can use this to create your own root kernels as Chainfire has done, or modify as you want. Refer to the Q&A above!
Click to expand...
Click to collapse
Hi..I notice there's an embedded kernel in the packer directory, but the path is an older version than the actual one in zimage. Is third just for pearl script purposes? Thanks
Sent from my GT-I9100
Hey RyanZA,
Following your script
> cpio -i --no-absolute-filenames < ../initramfs.img
extracts initramfs but gives me the error:
cpio: ../init: Cannot symlink to 'sbin-ueventd': Operation not permitted
Can you help a linux newbie here ? Do I need to be root?
EDIT: Ah! I think I know now... FAT does not support symlinks Going to ext...
Ok got the initramfs extracted from a zImage. Used repacker to create the zImage again. Did not change anything in initramfs. Filesize 5mb vs 8mb for the original. After a closer look I see that original contains lots of zeros. Ok appended zeros to match filesize and flashed the 'new' kernel. No go. Yellow triangle and no boot. Waited a long time.
Can anyone help? Maybe the repacker does something wrong? Maybe it should not compress?
Sent from my GT-I9100 using XDA Premium App
Anybody had any luck with this?
After said tweaking to get the repacker script running I got it to build a new zImage.
But mine was even only ~2MB small.... (seeing that the extracted initramfs summs up to about 3MB it makes at least a bit of sense, but still wondering).
Also the older kernel used (.29 against .35 that's actually running on my phone) makes me ....
Well, flashed it anyway but (as expected) it didn't work, phone showed the bootlogo and that's it, not even recovery worked.
So, is it the older kernel? Or is it forking up the initramfs image creation?
Or is there another way to rebuilt the kernel image with a new initramfs image?
I'd really like to get rebuilding the zImage working so I toy around with that a bit, try to make my own root kernel and all that funstuff
HellcatDroid said:
Anybody had any luck with this?
After said tweaking to get the repacker script running I got it to build a new zImage.
But mine was even only ~2MB small.... (seeing that the extracted initramfs summs up to about 3MB it makes at least a bit of sense, but still wondering).
Also the older kernel used (.29 against .35 that's actually running on my phone) makes me ....
Well, flashed it anyway but (as expected) it didn't work, phone showed the bootlogo and that's it, not even recovery worked.
So, is it the older kernel? Or is it forking up the initramfs image creation?
Or is there another way to rebuilt the kernel image with a new initramfs image?
I'd really like to get rebuilding the zImage working so I toy around with that a bit, try to make my own root kernel and all that funstuff
Click to expand...
Click to collapse
the fist script actually works good to pull initramfs. but I don't know about the repacker...better to build new
Yeah, trying to build a new kernel from sources at the moment (make is running as I type this).
Here's an idea why the rebuilder fails:
.29 kernel (that the rebuild script brings in and uses) but the initramfs has .35 version kernel modules (as it's for/from the .35 kernel)!
Not sure how delicate this version missmatch is, but there's a chance the one or the other important kernel module erroring out upon boot due to the version missmatch....
Well, let's see if a full build from sources works (as I know my luck, it won't....)....
that's because zImage has SFX code which tied very much to data (Image.gz). So you cannot just re-pack it back to existing zImage. You have to download source code of i9100 kernel and execute final part of kernel build where Image binary gets compressed and pre-pended by sfx header.
RyanZA said:
Following bash script to use it:
Code:
end=`repacker/findcpio.pl kernel.img | cut -f 2`
(cd initramfshere/; find . | cpio --quiet -R 0:0 -H newc -o > ../newinitramfs.img)
gzip -f9c newinitramfs.img > newinitramfs.img.gz
repacker/kernel_repacker.sh zImage newinitramfs.img.gz
Click to expand...
Click to collapse
err... the repacker/kernel_repacker.sh script only takes one argument.. how is it supposed to work???
sorg said:
that's because zImage has SFX code which tied very much to data (Image.gz). So you cannot just re-pack it back to existing zImage. You have to download source code of i9100 kernel and execute final part of kernel build where Image binary gets compressed and pre-pended by sfx header.
Click to expand...
Click to collapse
Yeah, that is actually what the repacker script does!
It has precomplied objects and compiles/links them together to the final (new) zImage.
saturn_de said:
err... the repacker/kernel_repacker.sh script only takes one argument.. how is it supposed to work???
Click to expand...
Click to collapse
You only pass the newinitramfs.img.gz that's created in the lines above, just drop the "zImage" from the commandline.
// EDIT
OK, I got as far as to compile my own kernel from the sources Samsung has released
I eventually end up with a nice and fresh, built from scratch zImage \o/
When I throw my selfmade zImage at the extractor script posted above, I get the proper (stock) initramfs filestructure I intended to put in (in other words, I managed to put my (as of now untouched) own initramfs.img into the zImage).
I create a nice .tar, flash with Odin and.... nothing
I get the bootsplash with the triangle and that's it, it doesn't get any further.
Anyone got a hint for me what I did wrong?
What I did:
(this all happened on a Linux machine)
extract Samy's kernel source
installed the codesourcery toolchain
set the CROSS_COMPILE var in ./kernel/Makefile to the proper path to the toolchain
ran
make c1_rev02_defconfig (according to readme.txt)
and then
make zImage CONFIG_INITRAMFS_SOURCE="/path/to/extracted/stock/initramfs/"
padded with 0x00s to the 8MiB size, tar'ed and Odin'ed
which brings me to the dead bootscreen....
Not even recovery works.
HellcatDroid said:
Yeah, that is actually what the repacker script does!
It has precomplied objects and compiles/links them together to the final (new) zImage.
Click to expand...
Click to collapse
I guess you've got repacker from first Galaxy?
It won't work. SFX header you're trying to compile is for first galaxy. It has hardcoded addresses and they are not compatible with Galaxy S II. Toolchain is also for SGS as well (not sure if it still suitable for SGSII).
Take kernel source code and toolchain for SGSII and it will work.
Yah, well, I got the kernel to compile fresh from sources now, no need for a repacker anymore, I just go make zImage and be happycat
Someone knows how to repack it?
Maybe Chainfire or Pulser?
Agreed, Can someone explain the process in full? modyfying and repacking zImage gets 2mb+ less in size, what we are missing?
Grooby said:
Agreed, Can someone explain the process in full? modyfying and repacking zImage gets 2mb+ less in size, what we are missing?
Click to expand...
Click to collapse
Necro much?
rawat said:
necro much?
Click to expand...
Click to collapse
zombie thread wants braaaaiiiiiiinnnnnnnnnnnnzzzzzzzzzzzzzz!!!!!!
Looks like i raised death searching for answer lool
A few tried to make repackers for the I9100 - and failed.
Even less know how to actually do it - and don't share the knownledge.
The thing is, that the initramfs is linked into the zImage during compile time, so it can't simply be "snipped out" and "new one pasted in".
That's why I eventually ended up compiling the whole thing from sources.
It would certainly nice if someone like ChainFire could share how to do it.... but he's too worried about others rebuilding his rootkernel with other nametags on it.
HellcatDroid said:
A few tried to make repackers for the I9100 - and failed.
Even less know how to actually do it - and don't share the knownledge.
The thing is, that the initramfs is linked into the zImage during compile time, so it can't simply be "snipped out" and "new one pasted in".
That's why I eventually ended up compiling the whole thing from sources.
It would certainly nice if someone like ChainFire could share how to do it.... but he's too worried about others rebuilding his rootkernel with other nametags on it.
Click to expand...
Click to collapse
GitHub.com/xiaolu
Sent from my GT-I9100 using xda premium
Where do I find these in the kernel source? Or is it possible to edit these from a zimage?
Look at http://android.git.kernel.org/?p=kernel/common.git;a=tree;f=drivers/cpufreq
Generally, editing compiled kernel isn't possible. But often you can pull your actual config by:
Code:
zcat /proc/config.gz
You can run it in adb shell.
the update file released by htc for htc desire 616 contains a read me file showing how to use the update but i cannot understand it if someone can explain i would be so greatful
defconfig file: a3ul_defconfig (arm-eabi-4.7)
Download:
=========
If you are not already using an AOSP toolchain (included in an AOSP build tree), download the corresponding official android toolchain for the arm-eabi specified above for this device:
git clone https://android.googlesource.com/platform/prebuilt for 4.4.3
git clone https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6 for 4.6
git clone https://android.googlesource.com/platform/prebuilts/gcc/darwin-x86/arm/arm-eabi-4.7 for 4.7
(use darwin-x86 in place of linux-x86 for mac)
Build the kernel:
=================
set the following environment variables:
export TOP= [where you installed the toolchain or top of android AOSP code base]
export PATH=$TOP/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin:$PATH (use corresponding arm-eabi bin path)
export ARCH=arm
export SUBARCH=arm
export CROSS_COMPILE=arm-eabi-
make [the defconfig file for this device above]
make clean (for subsequent builds)
make -j4 (in this example 4 is the number of processors of your build machine)
Output Binary Files:
====================
After the build process is finished, there should be a file named "zImage" found in arch/arm/boot/
If you are building a rom with this kernel ZImage, copy it into your build's output folder and rename it to "kernel".
You will also need the following kernel modules. These will eventually be installed into /system/lib/modules on the device.
kernel modules:
./driver/*.ko
If you have already built and installed a boot.img with root access you can also install the modules directly into the device using "adb remount" and "apb push [file] system/lib/modules/" for each file listed above. After installing files set permissions with "adb shell chmod 0644 system/lib/modules/*" and "adb reboot"
For additional information:
===========================
http://htcdev.com
honeyman_1989 said:
the update file released by htc for htc desire 616 contains a read me file showing how to use the update but i cannot understand it if someone can explain i would be so greatful
defconfig file: a3ul_defconfig (arm-eabi-4.7)
Download:
=========
If you are not already using an AOSP toolchain (included in an AOSP build tree), download the corresponding official android toolchain for the arm-eabi specified above for this device:
git clone https://android.googlesource.com/platform/prebuilt for 4.4.3
git clone https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6 for 4.6
git clone https://android.googlesource.com/platform/prebuilts/gcc/darwin-x86/arm/arm-eabi-4.7 for 4.7
(use darwin-x86 in place of linux-x86 for mac)
Build the kernel:
=================
set the following environment variables:
export TOP= [where you installed the toolchain or top of android AOSP code base]
export PATH=$TOP/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6/bin:$PATH (use corresponding arm-eabi bin path)
export ARCH=arm
export SUBARCH=arm
export CROSS_COMPILE=arm-eabi-
make [the defconfig file for this device above]
make clean (for subsequent builds)
make -j4 (in this example 4 is the number of processors of your build machine)
Output Binary Files:
====================
After the build process is finished, there should be a file named "zImage" found in arch/arm/boot/
If you are building a rom with this kernel ZImage, copy it into your build's output folder and rename it to "kernel".
You will also need the following kernel modules. These will eventually be installed into /system/lib/modules on the device.
kernel modules:
./driver/*.ko
If you have already built and installed a boot.img with root access you can also install the modules directly into the device using "adb remount" and "apb push [file] system/lib/modules/" for each file listed above. After installing files set permissions with "adb shell chmod 0644 system/lib/modules/*" and "adb reboot"
For additional information:
===========================
http://htcdev.com
Click to expand...
Click to collapse
This procedure will give you a kernel,not a ROM.
Sent from a Cool Phone stuck with crappy KingUser
checkout these links
for rom compiling
http://xda-university.com/as-a-developer/getting-started-building-android-from-source
https://source.android.com/source/building.html
http://forum.xda-developers.com/showthread.php?t=2223690
http://forum.xda-developers.com/showthread.php?t=2754145
http://forum.xda-developers.com/showthread.php?t=2320007
https://www.youtube.com/watch?v=fN0v5H0Eoe4
if still have any question feel free to ask.
or pm me
Give the full build rom from HTC 616 for kitkat
Hi, I'm working on a custom ROM for the Samsung Galaxy S9 and I'd like to use the new lz4 compression feature of Odin v3.13.
There is no problem to flash lz4 compressed stock images, but Odin does not like my lz4 compressed images and comments this with "FAIL! LZ4 is invalid"
I tried different compression rates and flags but nothing helped. Does anyone know the correct instruction for creating Samsung compatible lz4 images?
used version lz4 v1.8.3
https://github.com/lz4/lz4/releases
Found the solution by myself, compared two compressed archives until I've found the right parameters:
For Odin 3.1.13 following options are needed:
lz4 -B6 --content-size in.img out.img.lz4
see: https://www.mankier.com/1/lz4
Good morning, could you guide me to as how you unzipped it (lz4 (file name) and compressed it lz4 -B6 --content-size in.img out.img.lz4
Buen dia, podrias orientarme como lo descomprimiste (lz4 (nombre archivo) y lo comprimiste lz4 -B6 --content-size in.img out.img.lz4
cloooned said:
Found the solution by myself, compared two compressed archives until I've found the right parameters:
For Odin 3.1.13 following options are needed:
lz4 -B6 --content-size in.img out.img.lz4
see: https://www.mankier.com/1/lz4
Click to expand...
Click to collapse
Thank you very much for this info, I am getting same error and failing trying to flash magisk patched boot image for Samsung M01 Core mobile. I actually created the lz4 boot img with a windows software and failing.
I used ubuntu to create lz4 with the args you given and it worked.
Now the original boot img and batched boot img have same size and am able to progress in flashing it.
GitHub - Evsio0n/rsce-go: Rockchip resource image (RSCE) Pack/Unpack Tool written in Go
Rockchip resource image (RSCE) Pack/Unpack Tool written in Go - GitHub - Evsio0n/rsce-go: Rockchip resource image (RSCE) Pack/Unpack Tool written in Go
github.com
Rockchip resources image(RSCE) is a binary file which contains device tree blob and additional resources (like vendor splash screen) and appears as boot.img-second on unpacking.
Author: @evsio0n
Usage-u: Unpack the RSCE file to the specified directory.
e.g. ./rsce_tool -u ./boot-second
-p: Pack the file to RSCE file.
e.g. ./rsce_tool -p ./rk-kernel.dtb -p ./logo.bmp -p ./logo-kernel.bmp
use it at your own risk.
Beautiful tool, beats manually doing it every single time.