Hi all
I thought I'd try and write an easy and simple guide on how I extract blobs from vendor updates, cause I couldn't find a guide online myself.
A few things first:
- I will be writing this guide on Windows. You will need to find the Linux/MacOS tools yourself cause this is what I use.
- I use Windows Subsystem for Linux in this guide. It's not needed, but will make your life a lot easier. Follow this guide if you haven't got it installed already.
- This will assume you know how to build a ROM, know what device/vendor trees are, have some slight knowledge of the command line and know how to use basic Git.
First, we need to grab an OTA. I own a MI 8 Lite, so I usually use xiaomi.eu to update my blobs as it's easy to capture the zips. Depends on your device.
Now you've captured your OTA, you need to get the blobs extracted out. I use UR-Tool on Windows 10 but it's completely your choice. I will be proceeding this tutorial with UR-Tool.
Extract your zip into the UR-Tool build environment. Run the tool and choose your zip, extract it, like here: https://i.imgur.com/Y50Y3IZ.png
Okay, so now we have two directories, system and vendor (I'm fairly sure if you're non-treble you'll have one folder which means you can skip this next step.)
Go into system, and remove the symlink named vendor. You can then copy in the vendor folder into system.
In my device tree, I also had /sbin/charge needed in my proprietary-files.txt. I needed to extract my boot.img and put this folder into the system folder. Just check your device tree's needed files.
Copy the entire folder to somewhere easy to find and preferably a path which doesn't contain any spaces. We will be using it later.
Okay, so now we've done all this, we are going to move to the vendor and Git side of things. I will be using WSL from here!
So, now we have our fully ready to go blobs... but what now?
Well we need to prepare our vendor of course!
Like I said above I'll be using WSL from here as I needed "patchelf" for mlipay blobs. You will need something that can execute .sh files and using WSL is probably the easier option. If you're on Linux you don't need to do anything really.
We need 3 things to clone in. I've taken the liberty of stripping down Lineage's vendor to just the critical stuff for extracting blobs. You can find my repository here.
Lets make a new directory. We will clone in our trees like this:
Code:
git clone (device tree link) device/(vendor)/(codename)
git clone (vendor tree link) vendor/(vendor)/(codename)
git clone https://github.com/nysadev/extract_blobs_vendor vendor/lineage
This will create a directory that looks like a ROM, but severely stripped down. The reason we do the folders like this is because the scripts in device tree will point to a structure like this. This will help us avoid script location errors later. Make sure in your device tree that extract-files.sh points to vendor/lineage (should be in the first few lines).
Your root directory now should look like this: https://i.imgur.com/YiqMaDJ.png
Now go to your device tree. This is where all the good stuff happens. You need to know the path here of your extracted blobs from earlier.
Run these two commands:
Code:
chmod +x setup-makefiles.sh
./extract-files.sh (path/to/your/extracted/system)
Hopefully if all goes well you should see this with no "file missing in source errors": https://i.imgur.com/jErpyCv.png
Just to be sure, at the end of when it extracts, run "./extract-files.sh" again, just to prepare your vendor.
Now you're done! You'll hopefully see a few good modified libs, changes to Android.mk and your device-vendor.mk.
You're probably going to want to use git here to upload your changes. Just run:
Code:
git add .
git commit -m "(codename): update to (ota-version)"
git push -f
or something of the sort.
Well done! You're now done! Feel free to reply with any errors you get.
My Telegram is @nysadev; you're maybe better off catching me there.
I hope my guide helped you. Drop a like or something, idek.
It will be very useful
You rock! Love ya
how do u get proprietary-files.txt if u r building from scratch?
wheres UR-tool?
Related
This is a basic kernel build guide, to help those that keep coming into IRC asking for help.
If you follow this, you should have a working kernel that will work with ext4 or RFS.
NOTE::I wrote this at 1am, when Im kinda falling asleep, so there might be errors. Please let me know, and Ill fix it up
What you need:
A Linux system, with about 2gb free (This is written for 32bit systems, 64bit will need a compatible toolchain)
Development libraries
The kernel source
An ARM toolchain
An initramfs from an existing kernel
Downloads
EB13 source - search for D700 under mobile phone
Code Sourcery 2009q3 ARM toolchain
Daemon's Ext4/RFS Initramfs
Steps:
Set up the build environment
The first thing you need to do is set up the build environment.
For Ubuntu or other Debian-based system, you need the build-essential package and libncurses.
You can install this by running this command:
Code:
sudo apt-get install build-essential libncurses5-dev
If your not running Ubuntu/Debian, the packages are gcc, g++, libc-dev, and make.
Next, your going to need a directory for all your kernel build. You can't have spaces in any folder name. Im going to use /home/tortel/build/ for the rest of this guide.
Now you need to extract the kernel source to your directory. In the Samsung source file, its SPH-D700_kernel.tar
Next, extract the ARM toolchain into your build directory.
Last, extract your initramfs into the directory.
After this, your build directory should contain 4 things:
Code:
arm-2009q3/
eb13init/
Kernel/
build.sh
For this guide, Im not going to use the build.sh. If you want to, you'll need to configure that yourself.
Configure your kernel
Now the fun begins.
You need to edit the Kernel/Makefile file, and change line 184 to match where your toolchain is. My line 184:
Code:
CROSS_COMPILE ?= /home/tortel/build/arm2009q3/bin/arm-none-linux-gnueabi-
Now you need to configure the kernel.
The kernel configuration file is called .config, which is hidden by default (Ctrl+H shows hidden files in GNOME). You need to set lines 81-91, so it uses your initramfs. My lines:
Code:
CONFIG_BLK_DEV_INITRD=y
CONFIG_INITRAMFS_SOURCE="/home/tortel/kernel/eb13init/"
CONFIG_INITRAMFS_ROOT_UID=0
CONFIG_INITRAMFS_ROOT_GID=0
CONFIG_RD_GZIP=y
CONFIG_RD_BZIP2=y
CONFIG_RD_LZMA=y
# CONFIG_INITRAMFS_COMPRESSION_NONE is not set
CONFIG_INITRAMFS_COMPRESSION_GZIP=y
# CONFIG_INITRAMFS_COMPRESSION_BZIP2 is not set
# CONFIG_INITRAMFS_COMPRESSION_LZMA is not set
This will build your initramfs into the kernel image.
Now, your set to build.
Build the kernel
This is the easy part. Open a terminal, cd to build/Kernel and run make.
The commands:
Code:
cd build/Kernel/
make
If you have more than one core, you should add -j {1+ # of CPU cores} to make so it finishes faster. It only takes about 5min on my 2ghz C2D laptop.
Make it flashable!
Congrats, its built!
The file you want is Kernel/arch/arm/boot/zImage in your kernel source directory. After make finishes, run:
Code:
cp arch/arm/boot/zImage ..
This copies your kernel image file into your main build directory. Now, you need to put it into a flashable zip. To make it easy, here. Just throw the zImage into the root of that zip, put it on your SD card, and flash it.
Might want later
Advanced config stuff to come
Might want this too
Thank you for this, I'm glad too see this and others who have contributed great guides like this.
sent from "The Other Woman"
I was one of those people who kept bothering lol. I learned how to compile a kernal in two day though, now im on my way making a OC/UV Voodoo color kernal (coming soon) :]
Thanks alot
globalninja said:
I was one of those people who kept bothering lol. I learned how to compile a kernal in two day though, now im on my way making a OC/UV Voodoo color kernal (coming soon) :]
Thanks alot
Click to expand...
Click to collapse
what should I look into for making the changes necessary for an overclocking kernel?
Thanks for this helpful thread, and I had a question previously, that someone pm'ed me for. OP, please remove this reply if you feel inclined to. I had a question about the initramfs because my computer was having problems loading the page for the link.
Hey guys, kindof a noob to this.
How can I get an initramfs for DI18? Ideally, I could just use the one in the stock ROM unmodified, but I have no idea how to obtain it.
I figured it out! Used the scripts here to extract it from zImage:
http://forum.xda-developers.com/showthread.php?t=901152
This thread aims to be a comprehensive guide to building and packaging kernels for US Variant Samsung Galaxy SIIIs
In my opinion, a kernel is a great way to get into building things for your device and its pretty easy to do too.
Intro
What is a kernel?
http://en.wikipedia.org/wiki/Kernel_(computing)
This guide is for US SGSIII's (d2att,d2cri,d2mtr,d2spr,d2tmo,d2usc,d2vzw,others?)
It may be possible to adapt this to other devices, but I am not responsible for anything that happens should you try to do this.
This guide assumes you have a general knowledge of the Linux operating system. If you've never used it, you might consider playing around
with it for awhile before attempting this guide.
Click to expand...
Click to collapse
Prerequisites
On all devices you must be rooted, on Verizon SGS3 (d2vzw) you must also have the unlocked (VRALE6) bootloader installed.
This is not the thread for figuring out how to do this. You can use the forum's search function to figure out how to do this on your device.
You'll need a computer or a virtual machine running ubuntu. You may be able to figure out how to get this working on other distributions,
but since ubuntu is generally the most accepted distribution to use for building android things, I'll stick to using that here.
At the time of this writing, I'm using ubuntu 12.10, 64-bit.
You'll need to install some packages on your ubuntu machine:
Code:
sudo apt-get install build-essential git zip unzip
On 64-bit you'll also need some multilib and 32-bit compatibility packages:
Code:
sudo apt-get install gcc-multilib g++-multilib lib32z1-dev
Click to expand...
Click to collapse
Setting up the Build Environment
Next, you'll need a toolchain which is used to actually build the kernel. You may download one of these:
GCC 4.4.3: Download || Mirror
GCC 4.6: Download || Mirror
GCC 4.7: Download || Mirror
If you aren't sure, go for 4.4.3 or 4.6.
4.7 requires some code changes to work. The original kernel developer may or may not have made these changes.
Here is what I needed to do in order for 4.7 to build, boot and have wifi work:
https://github.com/invisiblek/linux-msm-d2/commit/f8d7199d37cfbfa1bcb6b4bcae3fc15ae71fbdea
https://github.com/invisiblek/linux-msm-d2/commit/ea58076501e5874db7b934c215c4dae81ddfd0a6
The toolchains are also available in the android NDK.
*** There are many toolchains out there, some of you may know of the Linaro toolchain which is aimed to optimize your binary even further ***
*** If you choose to use a different toolchain, that is fine. Keep in mind that you may run into issues depending on the toolchain you use ***
You can check what your currently running kernel was built with by issuing these commands:
Code:
adb root
adb shell cat /proc/version
It should return something like:
Linux version 3.4.0-cyanogenmod-gc4f332c-00230-g93fb4aa-dirty ([email protected]) (gcc version 4.7 (GCC) ) #134 SMP PREEMPT Thu Feb 28 00:22:41 CST 2013
Click to expand...
Click to collapse
This shows my particular kernel here was built with GCC 4.7
You can use wget to download one of the links from above, in this instance we'll download version 4.4.3 from the first link:
Code:
wget http://invisiblek.org/arm-eabi-4.4.3.tar.bz2
Extract this to somewhere you will remember, probably your home directory.
Code:
mkdir arm-eabi-4.4.3
tar -xf arm-eabi-4.4.3.tar.bz2 -C arm-eabi-4.4.3/
Click to expand...
Click to collapse
Obtaining Source
Find someone's source to use as a base. This can be a source archive from Samsung, a kernel tree from CyanogenMod, or any other developer around that makes kernels for your device.
TIMEOUT
This is a good spot to stop and take note that the Linux kernel is licensed under the GNU General Public License (GPL): http://www.gnu.org/licenses/gpl-2.0.html
What does this mean you ask? It means that if you plan to share your kernel with the community (if it's good, please do so!) then you MUST share your
source code as well. I am not liable for what you choose to do once you start building kernels, but know this: if you share your kernel and do not
provide source code for it, you will get warnings from XDA for a determined amount of time, after that you may have your threads closed, deleted and
possibly your user account terminated. This is extremely important!
Also, you may run into more problems than just XDA. There are organizations out there that do take action if you consistently refuse to comply with the GPL.
I recommend you read this: http://www.gnu.org/licenses/gpl-2.0.html so that you are familiar with what legalities you are getting yourself into.
The main thing to remember is to share your source code if you decide to share your built kernel.
Click to expand...
Click to collapse
In this instance, we will use CyanogenMod's kernel source for the US Galaxy S3's. You may browse the source code here:
https://github.com/CyanogenMod/android_kernel_samsung_d2
You'll notice that the branch there is cm-10.1
This is the default branch of this repository on github. This means that if you intend to build this branch, you'll need to use it on CM version 10.1. Most
likely it will not function on another version.
To obtain the source code:
Code:
git clone https://github.com/CyanogenMod/android_kernel_samsung_d2
This will take a little while, be patient.
When done, you'll have a directory called android_kernel_samsung_d2, cd into this directory.
Code:
cd android_kernel_samsung_d2
Next, you'll need to set up a couple environment variables. These tell the system two things:
1. What CPU architecture to build for, in this case arm
2. Where to find the toolchain we downloaded earlier, so that the system can cross compile for arm
Code:
export ARCH=arm
export CROSS_COMPILE=~/arm-eabi-4.4.3/bin/arm-eabi-
You'll need to set these variables on each new session. You can modify your Makefile in the root of your kernel tree in order to have these set permanently.
Click to expand...
Click to collapse
Building
At this point you can make any changes to the source code that you want. If this is your first time, I recommend not making any changes and make sure you have a
sane build environment before adding any complications.
When you build a kernel, you need to choose a defconfig. This is a specialized configuration file, specifically tailored for your device.
CyanogenMod names their defconfigs for their devices like so: cyanogen_<device>_defconfig and they are located in arch/arm/configs/
Code:
ls arch/arm/configs/cyanogen*
In this example, we will build for d2vzw.
Set up your tree to build for the d2vzw:
Code:
make cyanogen_d2vzw_defconfig
(do this in your kernel's root directory, in this example it was android_kernel_samsung_d2/ )
Now you are ready to build:
First, determine how many cpu's your computer has. You'll use this number to determine how many jobs the compiler command will use. The more jobs you can use, the more
cpu threads the compile will take advantage of, thus you'll get faster builds. If you don't know, just assume you'll use the number 2. We'll use 2 as an example here.
Code:
make -j2
Where 2 is the number of CPU cores your build system has.
And now we wait...until it's done compiling...
You'll know it successfully compiled when you have this line when it stops:
Kernel: arch/arm/boot/zImage is ready
Click to expand...
Click to collapse
PROTIP:
If it stops somewhere other than "zImage is ready" then you had build errors. Try running the 'make' command with no options after it. This will run the compile on a single thread
and will cause it to stop compiling as soon as it hits an error. When you run it on multiple threads, it definitely goes much faster, but if an error occurs, the console doesn't stop
until it finishes all of its threads. Causing you to have to scroll up and search around for an error
Click to expand...
Click to collapse
Now, assuming the build completed successfully, you have two things you are concerned with: A zImage (the kernel binary itself) and your kernel modules, which get built based
on what was configured in your defconfig.
You'll find your zImage at: arch/arm/boot/zImage
Code:
ls arch/arm/boot/zImage
The modules are scattered all over the place, depending on where the source existed that they were compiled from. We can easily search for them using this command:
Code:
find . -name "*.ko"
If both of the previous commands completed, you are now ready to package your kernel up for testing.
Move up a directory before continuing.
Code:
cd ..
Click to expand...
Click to collapse
Packaging
You may know of an awesome developer by the name of koush.
Well, once upon a time, koush created a rather simple zip, called AnyKernel, that would flash a kernel on a device, regardless of what ramdisk the kernel has on it.
I've taken his zip and modified it for d2 devices and to work with the newer recoveries out there.
This has a script in it that will dump your current boot.img (kernel+ramdisk), unpack it, replace the kernel, repack it and flash it.
It'll also copy any modules to the proper directory (/system/lib/modules) and set permissions appropriately.
You can get a zip here: Download || Mirror
(You can get it here as well: https://github.com/invisiblek/AnyKernel )
(Everyone is invited to use this zip, it'll probably make your life easier to not have to worry about the ramdisk. Enjoy!)
IMPORTANT
This AnyKernel package is for US variations of the Galaxy S3.
NOT the international (I9300) or any other device.
There are checks in the updater-script that will ensure you are running a d2 device before it does anything.
If you were to remove these checks, and not modify the partition that it flashes to later, you could end up with a brick.
If you intend to adapt this package for another device (please, do this! its a very handy script!), make sure you know it well, or ask someone to help you determine your device's
partition scheme before using it.
The risk here is due to the fact that the script doesn't know your device's partition scheme. It is configured specifically for the d2 devices. Flashing it on something else, who's boot
partition is somewhere else, might cause a bad flash to the bootloader partition (bad bad news if this happens).
Just be careful if you want to use this on another device. You won't run into problems if you use this on a d2 device.
EDIT: I made modifications that should make this less likely, but please, if you intend to use this on a different device (which is completely fine!) make sure you configure
the scripts to flash to the proper partitions.
Click to expand...
Click to collapse
Download and extract one of the above, we'll again use the first link for this example:
Code:
wget http://invisiblek.org/AnyKernel_samsung-d2.zip
unzip AnyKernel_samsung-d2.zip -d AnyKernel/
Now we'll copy our newly compiled zImage (still referring to the same kernel directory we used above, your repo might be called something different)
Code:
cp android_kernel_samsung_d2/arch/arm/boot/zImage AnyKernel/kernel/
cp `find android_kernel_samsung_d2 -name "*.ko"` AnyKernel/modules/
Finally we are ready to zip this up and test out flashing it.
Code:
cd AnyKernel
zip ../MyAwesomeKernel.zip -r *
cd ..
You'll now have a file named MyAwesomeKernel.zip which you should be able to flash via custom recovery (TWRP or CWM)
Click to expand...
Click to collapse
Extra Credit/Protips
Learn to use git. It's very powerful and great way to store your code.
Learn to use adb. It's an invaluable tool for any android developer.
Touchwiz and AOSP-based kernels are different. This means you cannot take CyanogenMod's source, build a kernel and expect it to work on a Touchwiz-based ROM.
Build a ROM next: http://wiki.cyanogenmod.org/w/Build_for_d2vzw
Crackflash your own stuff!
ALWAYS NANDROID!
Click to expand...
Click to collapse
Source code for all of my projects can be found here: http://github.com/invisiblek
FAQ
Q: How do I update my source tree to the latest that is available from where I downloaded it?
A: This can be handy if, for instance, you are building a CyanogenMod kernel and they added some patches, after you downloaded the source, that you want to include in your next build. You'll want to cd to your kernel tree and issue a git pull:
Code:
cd android_kernel_samsung_d2
git pull
You may then continue with the building instructions.
This may, however, have other problems if you've made changes to files. You might run into conflicts. I won't cover fixing any of this here, its not in the scope of this thread.
Q: I'm using X as a kernel base, but Y has a patch that I really like. How do I get it in my kernel easily?
A: I'll let you check Google for this answer, but I'll give you a hint use: git cherry-pick
Nice tutorial bro! Always good to learn something new everyday
Really is a good thread，thanks
This guide would have made things too easy for me.
Too easy, indeed. haha
Great job, invisiblek! AnyKernel is the beez neez.
Ok so this is a noob question but I gotta ask anyway lol. Ok so I cloned the kernel source, I made my edits, now how do I push all this to my github?
I already have a github account, I already made a new repo for the kernel. Here's a link to my github if you need it...
https://github.com/ghicks12/d2vzw_kernel.git
spc_hicks09 said:
Ok so this is a noob question but I gotta ask anyway lol. Ok so I cloned the kernel source, I made my edits, now how do I push all this to my github?
I already have a github account, I already made a new repo for the kernel. Here's a link to my github if you need it...
https://github.com/ghicks12/d2vzw_kernel.git
Click to expand...
Click to collapse
git remote add origin git_location_you_created_on_github.git
git push -u origin somebranch
The -u is for first time run only, you can just git push afterwards.
Sent from my SCH-I535
GideonX said:
git remote add origin git_location_you_created_on_github.git
git push -u origin somebranch
The -u is for first time run only, you can just git push afterwards.
Sent from my SCH-I535
Click to expand...
Click to collapse
Thanks! When I run
Code:
git remote add origin https://github.com/ghicks12/d2vzw_kernel.git
I get this back:
Code:
fatal: remote origin already exists.
I'm editing a CM based kernel, not sure if that matters or not?
That just means you added the remote already. Just issue the push command then.
Sent from my SCH-I535
Why is this happening? I don't know what i did wrong
[email protected]:~/cm$ make VARIANT_DEFCONFIG=cyanogen_d2att_defconfig
scripts/kconfig/conf --silentoldconfig Kconfig
drivers/media/video/msm/Kconfig:123:warning: choice value used outside its choice group
drivers/media/video/msm/Kconfig:128:warning: choice value used outside its choice group
***
*** Configuration file ".config" not found!
***
*** Please run some configurator (e.g. "make oldconfig" or
*** "make menuconfig" or "make xconfig").
***
make[2]: *** [silentoldconfig] Error 1
make[1]: *** [silentoldconfig] Error 2
make: *** No rule to make target `include/config/auto.conf', needed by `include/config/kernel.release'. Stop.
[email protected]:~/cm$
Hey. I'm having some problems with some GIT terminology and procedures. I'm a .NET developer and I use TFS and SVN on a daily basis. Forgive me if this is complete off basis from what you'd do with GIT.
What I want to do is merge one branch into another branch. In other words I want to take the latest kernel source from my favorite dev and merge in the latest from cyanogen's 4.3 d2 branch. Is this a rebase thing? It doesn't seem like cherrypicking to me.
I have successfully compiled kernel and made modules.I inserted zImage and modules inside any kernel updater,flashed via TWRP.When reboot stuck in odin and it says could not do normal boot.
the tools needed :
You will need a PC if not you wouldn’t be reading this.
A Github account created with Git installed on your system and if possible some knowledge on git commands or time to research on them if not known.
For a head start on some commands please refer to the excellent guide on XDA by forum moderator eagleeyetom called [Guide] How to use Github and can be found by searching on xda developers website.
Some experience with terminal if using Linux
A device and vendor tree for your device
Your AOSP rom of choice
Some hours of your time to work on this
This can be done on any platform that has git supported so windows, linux or mac but you will need linux to build android. In this guide I shall be using linux as it’s my preferred system and my distribution of choice at the moment Zorin OS 6 as I have found it to be the fastest and least resource hungry OS for me so far. So all commands in this guide will be using terminal.
For a guide on how to setup an android environment please refer to the guide on how to compile from source found on XDA-U
and for git here - https://help.github.com/articles/set-up-git —->
This is a perfect tutorial and one needed to begin your learning process.
Throughout this guide I shall refer to device repo or device tree they mean the same thing. It’s just different ways I like to refer to them. It means the device repository.
Ok now to the tutorial :
Once git is setup we now want to look for the device’s repo …
If CM or another AOSP rom is already available for your device then look for the github page for it by either searching on google or looking for your developer’s github page.
Here is how one looks :
As shown above the name setup is usually something like android_device_manufacturer_device or device_manufacturer_device. This can be used to help find the device tree using a search engine.
Ok once we find that we are going to fork the device repo so we can edit it to work with the AOSP rom we are porting. As different roms use different configurations for their setup.
You can fork a project by clicking the fork button on the top right of the github page like so -
Once that’s done we’re going to need to fork your device’s proprietary vendor files. Cyanogenmod usually names their repos differently to some other teams so when searching for for a vendor repo for your device on Cyanogenmod it will be properietary_vendor_manufacturer, whereas others teams might just name it vendor_manufacturer.
Now once that’s done go to the github page of the AOSP rom that is being ported and also fork their vendor setup repo so we can add the device to the setup so it can be called later on when we run the . build/envsetup or source build/envsetup.sh command this allows us to compile the rom after when we have selected our target device.
Once that’s done we are now going to start cloning these repos onto your local machine so we can modify some files to add our device. Best way to do this is create a new directory where all the work is going to be done in your home folder and cd into that directory. So mkdir directory(name it whatever you want), then cd directory. So for example if the name of the new directory was named github then the commands will be mkdir github, cd github. Once that’s done navigate to your account page on github and clone the repos we forked earlier. To do this we look for the ssh url on each repo page then we copy it. Then we type git clone and paste the url and click enter on the keyboard. This will clone the repo from your github(remote) to your local(system) allowing you to make changes to the files then upload them back to github.
So when cloning is done the device, vendor tree and the rom’s vendor tree should be present. Now this is the part where we really need to switch on our brains. First go back to the github page of the rom’s vendor tree and click on commits now look through them and find one where a new device is added. Copy this new configuration and apply it to your device by either modifying existing files or creating new ones. To ensure no conflicts arise when envsetup.sh is ran try to make the product_name different but ensure the product_device and product_model are the same as the one in the device tree.
Once the device has been added what is left is to push the changes to your remote(github) by using the git push command. This can be done by first using git add -A which lets all the new files and changes to be tracked. Then we use the git commit -am ” message “. E.g git commit -am “Add defy to the mix”. This adds a commit message which will appear on our remote branch with the new changes. Finally we use git push origin to push the changes to our remote. E.g git push origin jellybean
Additionally look at some device setups on the rom’s github page and see if any changes are needed to make your device configuration compatible with the rom’s vendor tree. Usually none are need but it depends on how the person or team has setup their vendor tree.
Now this part is the longest and can be the most annoying process as we need to find the changes that are necessary to ensure the device boots when the rom has been compiled. This can be done in a number of ways but the best will be to kindly ask one of your device rom developer/s or member/s that have created the AOSP rom device tree that is been used to port the rom you’re porting. Depending on what type of device you have if it has a locked or unlocked bootloader then changes will have to be cherry-picked or merged in different places such as frameworks_base, system_core, etc.
Refer back to the git guide in the requirements on how to use these commands like git cherry-pick, git merge. I can’t really guide you here as each device is different so this is the part where you need your brain at maximum capacity.
Here you will be cloning all the repos where changes need to happen from the rom’s github page you’re porting. Then cherry-picking and merging these changes. Remember to first add the remote with git remote add before you start cherry-picking so the SHA number can be found.
Also remember to add your repos to the platform_mainfest or android(if it’s a CM based rom) Additionally, check your device maintainer’s setup to see if any additional repos any needed.
Once that has been resolved push the changes to your remote and make a new directory in your home directory then, repo init and repo sync, chose your device target with the lunch command and finally use mka to compile the rom. Pat yourself if it compile without errors.
Good Luck and Enjoy your hard work if it’s successful. However, if the unfortunate happens then report any issues here and me and the others members of XDA will try help out as this is XDA after all where we help each other, learn and expand our knowledge of Android.
Re: [GUIDE] Port AOSP ROMs using source code
Great guide, thx
exactly what i was looking for ... thanks OP
Nice guide!
Thank you a lot
I think you should change the title to "Compile AOSP from source" .
thachtunganh said:
Nice guide!
Thank you a lot
I think you should change the title to "Compile AOSP from source" .
Click to expand...
Click to collapse
changed
Sent from my Desire HD using xda app-developers app
Good to start with
A Good Guide to start with, Thanks a lot.
Nice work! Maybe add those screenshots "inline" so they flow with the text?
......... deleted....
Hi Folks
I wasn't sure where this should belong but as it is a bit of an Hack this forum is probably the most appropriate
Introduction
This short tutorial will show you how to patch the Android Build System to allow you to cross-compile Android AOSP host tools ( adb, fastboot etc ) for OSX using a linux based machine. This is something Google said was impossible or at the very least unsupported.
Assumptions
You have a linux based machine and working copy of the AOSP source tree.
You can/have successfully compile(d) a full Android Release from this tree.
A basic idea of how the Android Build System works is beneficial.
Getting Started
I've set-up a git repository which contains a binary copy of the OSX SDK 10.6 and the apple-darwin10-gcc cross compiler. So first things first. open a terminal and set the root of the AOSP sources tree to the current directory.
STAGE 1: Copy the OSX SDK
Step 1.
Clone the repo with the SDK and toolchain
Code:
git clone https://github.com/trevd/android_platform_build2.git build2
Step 2.
Create /Developer directory at your filesystem root, this is a known location for the SDKs
Code:
sudo mkdir /Developer
sudo chown $USER.$USER /Developer
Step 3.
Copy and unpack the SDK package
Code:
cp build2/osxsdks10.6.tar.gz /Developer
cd /Developer
tar -zxvf osxsdks10.6.tar.gz
rm osxsdks10.6.tar.gz
cd - # back to aosp root
STAGE 2 : Swapping the Toolchain
This is where the fun begins :laugh:
The Android Build system has the majority of the infrastructure in place already to build for OSX, the only problem is that you need OSX to build for OSX. However we can remedy that with a couple of dirty hacks :laugh:.
The prebuilts/gcc/darwin-x86 directory contains a toolchain compatible with osx ( mach-o binaries ). We are going to swap this for a linux compatible ( elf ) executables.
Step 4:
Copy and unpack the elf compatible darwin cross toolchain
Code:
cp build2/i686-apple-darwin-4.2.1.tar.gz prebuilts/gcc/linux-x86/host
cd prebuilts/gcc/linux-x86/host
tar -zxvf i686-apple-darwin-4.2.1.tar.gz
cd - # back to aosp root
Step 5:
Remove the mach-o binaries and symlink the elf binaries in it's place
Code:
cd prebuilts/gcc
rm -rf darwin-x86
ln -s linux-x86 darwin-x86
cd - # back to aosp root
Step 6:
We also need to replace the mach-o version of the ccache executable which live in the prebuilt/misc directory
Code:
cd prebuilts/misc
rm -rf darwin-x86
ln -s linux-x86 darwin-x86
cd - # back to aosp root
STAGE 3: Patching the build system .mk files
We need to patch a couple of files in the build directory namely the build/core/combo/HOST_darwin-x86.mk the main crux of this is swapping the ar tool for libtool so static libraries can be created without error.
Code:
patch -p1 < build2/build.patch
If the patch has been applied successfully you should see the following
Code:
patching file system/core/adb/Android.mk
patching file build/core/combo/HOST_darwin-x86.mk
patching file build/core/combo/select.mk
patching file build/core/envsetup.mk
patching file build/envsetup.sh
You are now ready to cross compile!! :good: ..... well not quite, but nearly.... here's why!
The Android Build System will attempt to build both the Target and Host files for most modules so I'd advise using a lunch option which already has a full target built for it or alternatively you can build the generic sdk using the following commands at the AOSP source tree root.
Code:
. build/envsetup.sh
lunch sdk-eng
make sdk
This will stop target dependency errors occurring when you build individual modules.
NOW we're ready to cross compile.
STAGE 4: Building Modules
At present module build is very much a piecemeal process. To build adb for example we need to build the dependencies first. This is not too onerous as most host modules have very few dependencies.
Building adb
adb has dependencies on the following libraries
Code:
external/zlib
external/openssl
system/core/liblog
system/core/libcutils
system/core/libzipfile
I've found the easiest way to compile the dependencies is to navigate to each directory in turn an use to "mm" build system command to compile the individual module. the commands I run to compile adb are as follows.
From AOSP Source Root
Code:
cd external/zlib
USE_DARWIN=true mm -j8
cd ../openssl
USE_DARWIN=true mm -j8
croot # go back to the AOSP root
cd system/core/liblog
USE_DARWIN=true mm -j8
cd ../libcutils
USE_DARWIN=true mm -j8
cd ../libzipfile/
USE_DARWIN=true mm -j8
cd ../adb
USE_DARWIN=true mm -j8
All being well you should now have and adb binary located at out/host/darwin-x86/bin/adb. running the file command on this binary should produce the following output
Code:
adb: Mach-O executable i386
Conclusion
Although this method is a little rough and ready, it should produce the desired results if you need to cross compile for OSX. The eventual goal would be to compile a full OSX Android SDK on linux in a similar manner to the way the windows-sdk is currently compiled. This requires more investigation as compiling the windows sdk on linux employs a little bit of trickery on the part of the build system.
Final Notes and FAQs:
Why can't I just type make <module> from the root?
Doing this triggers building of additional modules such as LLVM and clang which are to deployed out/host/darwin-x86/bin the build system then attempts to use binary later on. These are obviously built for the Mach-o architecture and as such are incompatible with the linux. This results in a build error which can and would be resolved by the above mentioned trickery ( see conclusion )
I use OSX binaries (along with Windows and my native Linux) in one of my projects. Thanks, I have always relied on finding compiled binaries elsewhere. Lack of an OSX aapt held up an update at one point.
One of those things that you don't really use until you need it, but I will try to remember to give it a shot. I don't have any doubt that it works.
mateorod said:
I use OSX binaries (along with Windows and my native Linux) in one of my projects. Thanks, I have always relied on finding compiled binaries elsewhere. Lack of an OSX aapt held up an update at one point.
One of those things that you don't really use until you need it, but I will try to remember to give it a shot. I don't have any doubt that it works.
Click to expand...
Click to collapse
Thanks. Yes this really is an edge case. Hopefully It will help some folks out.
Regarding aapt in particular.... It's perfectly possible to build aapt, however, we need to do some slight of hand with the clang and clang++ executables as libpng on which aapt depends uses these 2 binaries as part of it's build process.
Here's the build list and the clang trick if you want to try it some time.
Code:
build/libs/host
external/expat
external/zlib
system/core/liblog
system/core/libcutils
mkdir out/host/darwin-x86/bin
cp out/host/linux-x86/bin/clang out/host/darwin-x86/bin
cp out/host/linux-x86/bin/clang++ out/host/darwin-x86/bin
external/libpng
frameworks/base/libs/androidfw
frameworks/native/libs/utils
frameworks/base/tools/aapt
I started off with a clean out/host/darwin-x86 directory so I didn't miss any dependencies.
like I mentioned the clang "swap out" is something the make win_sdk option does automatically so with it a little more research I should be able to get the mac build to do the same but you'll have to "fill yer boots" with the ghetto method for now
For reference here's a link to the sdk building instructions http://tools.android.com/build which describes how to cross compile the windows sdk on linux ( in case anyone was wondering what the hell i'm on about)
My use case has come up
I will be cross-compiling for OSX today...specifically with aapt in mind. I will report back, but I fully expect it to work as described.
mateorod said:
My use case has come up
I will be cross-compiling for OSX today...specifically with aapt in mind. I will report back, but I fully expect it to work as described.
Click to expand...
Click to collapse
Cheers Man!
Hopefully no bitrot has crept in since april and now. I know I've changed my OS version since to Lubuntu 13.04, not like the OS version really matters any.
mateorod said:
but I fully expect it to work as described.
Click to expand...
Click to collapse
Then you Sir, are either Drunk or a Fool! LOL Keep expectations Quantum and only decided when the result is observed a'la Schrodinger Cat
okay...So I was trying to compile SlimRom (so as to get an OSX aapt binary with the SlimRom changes) and things did not necessarily go as planned. There were enough changes to the SlimRom android_build that your build/build.patch does not apply cleanly. I spent some time and tried to modify the patch so that it would work for both SlimRom, AOSP and probably others, but each android_build repo has some differences in surrounding the HOST_AR line, so commenting that just was not portable between flavors. Not cool.
Anyway, turns out that this method does not quite work out of the box for non-AOSP versions (not that you claimed that it did). I got some unfamiliar errors related to (I believe) some OSX toolchains. But in both times I tried this, I actually had to pretty immediately swap out of that flavor and so I was unable to do much debugging. (I keep all the flavors I build {CM, AOKP, SlimRom, PAC, PA, OpenPDroid, etc, etc, etc} all layered in one android/system/jellybean directory. It saves a ton of space, but only allows me to do one thing at a time.)
So the only feedback I have is nothing...I even formatted my hard drive in-between and forgot to put up a paste, so the errors are currently lost to history.
Things that I noticed, for better or worse
You recommend putting the SDKs in the root dir. I believe the documentation is recommending the Developer be placed in home (as per the SDK/ADT bundle docs).
You might want a
Code:
mv android_platform_build2 build2
line. I normally wouldn't bother, but it looks like you are trying to post a line-by-line guide.
I would put the recommendation that a full build be available to the out folder (or a built generic sdk) right at the top, since it is a preliminary step. I had to revert my handwritten changes, then build, then reapply the changes and rebuild since I thought it needed a clean out dir.
Did you have any trouble with git reverting the toolchain swap? On two separate machines, I had to go so far as to delete .repo/projects/prebuilts/gcc/* and prebuilts/gcc/darwin-x86/arm/arm-eabi-4.6. It kept complaining of that the project in the .repo folder was a bad match. No amount of git trickery (which I am not terrible at) let me back out more easily.
I am willing to try again...but I have some other small things to attend to first. It is an admirable hack you have here sir. I will return to it soon and report back once more.
mateorod said:
okay...So I was trying to compile SlimRom (so as to get an OSX aapt binary with the SlimRom changes) and things did not necessarily go as planned. There were enough changes to the SlimRom android_build that your build/build.patch does not apply cleanly. I spent some time and tried to modify the patch so that it would work for both SlimRom, AOSP and probably others, but each android_build repo has some differences in surrounding the HOST_AR line, so commenting that just was not portable between flavors. Not cool.
Anyway, turns out that this method does not quite work out of the box for non-AOSP versions (not that you claimed that it did). I got some unfamiliar errors related to (I believe) some OSX toolchains. But in both times I tried this, I actually had to pretty immediately swap out of that flavor and so I was unable to do much debugging. (I keep all the flavors I build {CM, AOKP, SlimRom, PAC, PA, OpenPDroid, etc, etc, etc} all layered in one android/system/jellybean directory. It saves a ton of space, but only allows me to do one thing at a time.)
So the only feedback I have is nothing...I even formatted my hard drive in-between and forgot to put up a paste, so the errors are currently lost to history.
Things that I noticed, for better or worse
You recommend putting the SDKs in the root dir. I believe the documentation is recommending the Developer be placed in home (as per the SDK/ADT bundle docs).
You might want a
Code:
mv android_platform_build2 build2
line. I normally wouldn't bother, but it looks like you are trying to post a line-by-line guide.
I would put the recommendation that a full build be available to the out folder (or a built generic sdk) right at the top, since it is a preliminary step. I had to revert my handwritten changes, then build, then reapply the changes and rebuild since I thought it needed a clean out dir.
Did you have any trouble with git reverting the toolchain swap? On two separate machines, I had to go so far as to delete .repo/projects/prebuilts/gcc/* and prebuilts/gcc/darwin-x86/arm/arm-eabi-4.6. It kept complaining of that the project in the .repo folder was a bad match. No amount of git trickery (which I am not terrible at) let me back out more easily.
I am willing to try again...but I have some other small things to attend to first. It is an admirable hack you have here sir. I will return to it soon and report back once more.
Click to expand...
Click to collapse
Hi
Thanks for this, It sounds like you've suffered an exercise in frustration there. I wasn't aware that "SlimRom" had a different aapt ( just out of general ignorance and not having paid any attention )
SDK - My Tree last time I used this was /Developer directory in the root - I think It comes from what the toolchain is expecting, I just gave it what it wants
mv android_platform_build2 build2 - Yep I did mean that it's the git clone line which wants changing
Code:
git clone https://github.com/trevd/android_platform_build2.git build2
SDK Recommendation - I shall move that to the top, even though it is already in there, It should probably be highlighted better and possible it's own "Stage"
Reverting the toolchain - Ahh , It appears I work slightly different from most in this respect. I have a general mistrust of SCM's ( I lost too much code on too many different SCM's, Probably through my own inability to use them correctly but ) what I do to revert to change is
Code:
cd prebuilts/gcc/darwin-x86/host/
rm -rf i686-apple-darwin-4.2.1
repo sync i686-apple-darwin-4.2.1
You can do this "trick" on any project in the source tree it's only on rare occasions where I screwed up badly that I have to delete anything in .repo/projects but I also have my distro in their own individual directories with there own full git trees, which is a massive waste of space and has a ton of redundancy due to the AOSP repositories being mirror by every single one but switching between them is a lot easier
If SlimRom's changes are localized to aapt, I'd be more inclined to drop it into the AOSP build and try that... If you have a link to slimrom's frameworks/base repository I'll grab it and try it myself.
On a final note there's a "full version" of the HOST_darwin make file in the build2/core/combo directory the changes to envsetup.mk and select.mk are minimal and can easily be applied manually. You don't need to patch the adb makefile if your not building it.
Again Thanks for the feedback
About this guide
I have been building kernels for many machine types and have been fiddling around with custom android kernels for my own phone but to my great frustration the rules changed quite a lot for my new phone. It seems every kernel after 2017 is A LOT harder to build and needs quite some fiddling around te get it to boot. The documentation is terrible the least on the steps and all howtos are all outdated by now. This guide shares with you the secrets to build yourself a modern post 2017 kernel from source. I only own a op7 at this moment but I am pretty sure the rules apply to all devices.
So why do we need to build our own kernel? Well that's simple. I have scrolled through many custom kernels missing a simple module that I need. In my case binfmt. Perhaps you need a specific device driver compiled into your kernel or you want to hack in/patch in some special functions that are only needed by you. Or you love a certain kernel but need that one little adjustment in the configs that this kernel doesn’t have and so on.
Lets get through it step by step but I do assume you know something about Linux, you know how to use the terminal and that you have some knowledge on building binaries from source. Ready? Ok lets get started.
These steps are required to be followed to be successful:
1. Set up a building environment
2. Obtain the kernel source
3. Download the proper tool-chain
4. Adjust configuration files to match your needs
5. Build the actual kernel image
6. Backup your current boot.img!!!
7. Trow the image into a anykernel zip and flash it.
8. Close your eyes prey and run the kernel.
Prerequisites
You will need:
A fairly fast computer with lets say 4 gigs of RAM and a decent CPU.
A workable linux distribution that you can boot into (I prefer ubuntu bionic at this moment).
The kernel sources for your device.
ROOT!!
Lots of spare time.
A attitude that makes you unstoppable.
1. Setting up the building environment
Ok lets first open a terminal. You will need the terminal a lot. As a matter of fact it will be your friend through this guide so better get used to it. Assuming you are on a ubuntu like distribution lets fetch the important packages first
Code:
$sudo apt install build-essential bizon flex git
This command will install some of the prerequisites you need to do anything. More packages will need to be installed on the way but at least you will be able to type $make
Now lets create a working directory. Go into your home folder and create a working directory which will later on contain your kernel sources and tool chain.
Code:
$cd
$mkdir [COLOR="MediumTurquoise"]name-of-your-working-folder[/COLOR]
2. Obtain the kernel source
This one is tricky as my experience have learned me the kernel sources supplied by my own vendor are usually badly documented and contain a few bugs here and there resulting in either build errors or a unbootable kernel. So usually I grab a custom kernel that has minimal changes to the stock kernel and boots by only using a single kernel file without extra kernel modules attached. The custom kernels usually have the nasty building bugs flawed out and thus your chances for success are higher. I used the exkernel in my case and out of respect for the hard work of flang2 I bought the app that came along.
To get the sources google around and find the sources on for example git and click the download or clone button there and copy the link of the depository.
Then simply clone the depository to your working directory so after changing to your working directory type
Code:
$git clone link-you-just-copied
Git will now automatically clone the entire kernel source into the source sub-directory. You can change the name of this directory to make you life easier.
3. Download the proper tool-chain
This is where I lost many days and weeks of my life. Where do we find the proper tool-chain for our kernel?
You basically need 3 compilers
clang
GCC
device-tree-compiler
There are many versions of clang and GCC and you will need to find the one that matches your kernel and builds for your cpu architecture. I will assume in this guide that your CPU is aarch64 or arm64 (both names are used at the same time).
To obtain clang head over to the following address:
"https://android.googlesource.com/platform/prebuilts/clang/host/linux-x86/"
now in the tags and branches you can find the version of android you are looking for. If your kernel is for android 9 then use the android 9 tag. Click on it and then click tgz which will provide you with a huge tarball.
Create a folder in your working directory named toolchain en extract the contents of the tarball into the sub-folder clang.
You can try any subversion of clang there is but I recommend to simply peek into the build.config files located in the root of your kernel source directory which usually specify the exact subversion of clang used.
Time to get GCC which is easier since there is only one version right now.
Head over to
"https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.9/"
and use the correct version here as well. In my case I picked the latest build. Then do the same as for clang but name the sub-folder GCC or whatever you please to do.
And then finally get yourself the device-tree-compiler
Head over to
"https://github.com/dgibson/dtc/tree/v1.4.4"
and clone this depository into ~/your-working-directory/toolchain/
and navigate to the subdir you cloned it into
then build by typing
Code:
$make
any missing package errors will need you to install them using
Code:
$sudo apt install missing-package-name
and do make again until the build completes.
If all went well your tool-chain and working directory will look like this:
Code:
/[COLOR="mediumturquoise"]current-working-dir[/COLOR]/[COLOR="mediumturquoise"]kernel-source-dir[/COLOR]/
|
/toolchain/
|
/clang/
/gcc/
/dtc/
4. Adjust configuration files to match your needs
Lets first grab the correct defconfig file and setup the build directory. This defconfig file contains the default kernel configuration parameters which you propably want to adjust.
Head over to ~/working-directory/kernel-source-dir/arch/arm64/configs/
see what you can find there. I found the elementalX_defconfig file which is the file I needed to build the Exkernel from scratch. If you are trying a stock kernel dive a little bit deeper into the vendor folder and see if you can find a good config file there.
Alternatively sometimes the config is hidden on your device itself. Have a look at
/proc/config.gz
the file inside the archive contains a valid defconfig for your device but beware your may need to open it with menuconfig first and save it again to make it workable for the compiler script.
Place the defconfig file you like to use into the configs folder.
(Skip the following step if your are going to build your kernel for the first time because we first want to see it work.)
Now head over to your kernel source dir and type the following command
Code:
$PATH="~/[COLOR="mediumturquoise"]working-dir[/COLOR]/toolchain/clang/[COLOR="mediumturquoise"]clang-r353983c[/COLOR]/bin:~/[COLOR="mediumturquoise"]working-dir[/COLOR]/toolchain/gcc/a[COLOR="mediumturquoise"]arch64-linux-android-4.9[/COLOR]/bin:${PATH}" \
make menuconfig O=out \
ARCH=arm64 \
CC=clang \
CLANG_TRIPLE=aarch64-linux-gnu- \
CROSS_COMPILE=aarch64-linux-android-
now remember to use the correct paths to your tool-chain. In this command I use clang-r353983c but you may use a different version. The same applies for linux-android-4.9.
I would like to thank Nathan Chance for supplying documentation on the clang tool-chain on his github.
If all well you will be presented with a menu in which you can adjust things. First open the defconfig file you wish to use and then save the file after you are done. Now REMEMBER! With this command the menuconfig will save your new file into the /kernel-source-dir/out folder.
(end of the skipped step)
Now it is time to prepare our kernel build using the following command (do this from your kernel source dir) and remember that this command will look in the /kernel-source-dir/arch/arm64/configs/ directory
$make O=out ARCH=arm64 name-of-your-defconfig
If all goes well you will see something like configuration written to .config
Everything is up and ready to go. Your hart will start pounding from this moment on
5. Build the actual kernel image
This is where things get complicated. I hope you have many years to live because this part consumes time, a lot of it.
type
Code:
$PATH="~/[COLOR="mediumturquoise"]working-dir[/COLOR]/toolchain/clang/[COLOR="mediumturquoise"]clang-r353983c[/COLOR]/bin:~/[COLOR="mediumturquoise"]working-dir[/COLOR]/toolchain/gcc/[COLOR="mediumturquoise"]aarch64-linux-android-4.9[/COLOR]/bin:${PATH}" \
make -j$(nproc --all) O=out \
ARCH=arm64 \
CC=clang \
DTC=~/[COLOR="mediumturquoise"]working-directory[/COLOR]/toolchain/dtc/dtc \
CLANG_TRIPLE=aarch64-linux-gnu- \
CROSS_COMPILE=aarch64-linux-android-
ready set GO!
This will depending on your machine take between forever and eternally. You will witness many warnings on the DTC build seems normal these days and a few warnings on the CC part. Most important is that no errors are thrown at you.
If all goes well you will see a normal exit status and you will have a “working” kernel image.
“Error?: Well that happens. Try a different build of clang check your command line. And if all that fails try to find out what is wrong in the source and that means digging through thousands of forum pages until you find out whats wrong. But using the google tools usually goes well.”
Almost there go and check
kernel-source-dir/out/arch/arm64/boot
and there should be a image-dtb or image.gz-dtb file depending on you settings.
That is your kernel image right there. The difference in size between image and image-dtb should not be huge. 10Megs in difference usually means your dtb is not good but trying is the only way to find out if it works.
6. Backup your current boot.img!!!
You know what to do here right? Do not skip this step unless you like bricked devices or want to reflash and lose your data and all that kind of stuff. Not sure what you are doing stop here or backup your entire device including system vendor etc.
7. Trow the image into a anykernel zip and flash it.
Ok something changed in the last few years. Unpacking repacking and booting using fastboot somehow gives me problems. Dm-verity errors and all kind of red screens. Signing the boot image results into new errors. Well this is how I did it.
Get yourself a anykernel zip file. I used the Exkernel.zip because it only contains a kernel image which I like. Open the zip in a good zip tool (I used ark) and replace the image-dtb file with the one you created. Place this new zip you created on a memory stick and then….
Flash it using twrp or any tool of choice.
8. Close your eyes prey and run the kernel.
Two things can happen.
1. Blank screen nothing happens. Only god can help you, repeat all the steps.
2. Your android starts booting. Start crying of joy
Check in your android if this is indeed the kernel you build. If so time to make some adjustments to your configs or happily enjoy your boosted phone.
Now please remember. If you plan to distribute your kernel that you do the correct steps of accrediting the original programmer and trow the source online. If you use a already custom kernel please respect the hard work of the maker and communicate your plans with him/her.