Looking to create your own custom kernel? Start here! - Note 7 Guides, News, & Discussion

INTRODUCTION
I create this guide in the hope to jump start development on our lovely Exynos devices.
I expect that before you start, you have a Linux installation in either a virtual machine or on a physical PC.
Debian Jessie, Kali Linux, Mint, or Ubuntu are excellent choices and what I'm familiar with, so if you get stuck it'll be easier for me to help you if you use these.
PREREQUISITES
WARNING: Custom kernels on the Note 7, S7, and S7 edge currently require encryption to be disabled in order to boot. They also have to disable some secure MobiCore firmware. You will have to format your entire data partition when going from stock kernel to a custom kernel! Once you're on a custom kernel with non-encrypted data, you shouldn't have to wipe it going to another custom kernel.
Be careful not to disable developer options or OEM unlock, otherwise all your data will be destroyed! Back up your data partition whenever you flash stock. (for upgrades, etc.)
First off, you'll want to download some tools necessary for building and downloading kernel sources:
git-core - you'll want git for downloading and maintaining your sources
build-essential - native gcc & tools for building (needed for build commands)
libncurses5-dev - needed to build menuconfig
diff - used to compare config changes
colordiff - used by diff to provide colorful human readable diff output
Code:
apt-get install git-core build-essential libncurses5-dev diff colordiff
PREPARING YOUR ENVIRONMENT
Once you've got that out of the way, you should create an organized environment for working. I like to use ~/build.
Code:
mkdir -p ~/build/toolchain ~/build/kernel
DOWNLOADING & INSTALLING A TOOLCHAIN
You'll want to download a toolchain for kernel building. I recommend using Linaro's optimized ARM toolchains.
The Exynos 8890 benefits from the Cortex-A53 code compiling optimizations.
GCC 4.9: https://releases.linaro.org/components/toolchain/binaries/4.9-2016.02/aarch64-linux-gnu/
GCC 5.X: https://releases.linaro.org/components/toolchain/binaries/latest-5/aarch64-linux-gnu/
The actual file that you want ends in -x86_64_aarch64-linux-gnu.tar.xz (assuming you have a 64-bit Linux install, seriously, 32-bit needs to go! )
We'll use the GCC 5.3.1 2016.5 toolchain in this example.
Let's download and extract it now:
Code:
cd ~/build/toolchain
wget "https://releases.linaro.org/components/toolchain/binaries/latest-5/aarch64-linux-gnu/gcc-linaro-5.3.1-2016.05-x86_64_aarch64-linux-gnu.tar.xz"
tar xf ./*linux-gnu.tar.xz
rm ./*linux-gnu.tar.xz
That's it for installing the toolchain, easy right?
DOWNLOADING THE KERNEL
Rather than download your kernel sources directly from Samsung full of wacky issues when you change a single configuration option, you can grab it from my GitHub!
Using this method, you have an already working stock kernel prepared to be modified and built at your leisure.
You're also able to grab updates and fixes from me should you want them. I'll be committing new kernel source updates from Samsung to the opensource branch.
The stock-6.0 branch will be rebased on top of opensource when that happens, then stock-6.0.y (stock, with Linux updates) will be rebased on top of that.
Cool concept, right?
First, you'll want to create a GitHub account if you don't have one already.
This will allow you to upload your changes and share your kernel with other interested users and developers.
Once you've got your account, and you're logged in, browse to:
https://github.com/jcadduono/android_kernel_samsung_universal8890
You want to fork the sources to your own account, to do this simply click the [Fork | ] button near the top right of the page:
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Now you've got your own copy of the Note 7 / S7 / S7 edge kernel sources on your GitHub!
The next step is to use git to download it to your PC.
Replace "your_username" with your actual GitHub username. Using [email protected] you can avoid being asked for your username each time you push new changes.
Code:
cd ~/build/kernel
git clone https://[email protected]/your_username/android_kernel_samsung_universal8890 samsung_universal8890
cd samsung_universal8890
The default branch is stock-6.0. This is what most users will want. If you wish to start on a kernel that is updated to the latest Linux minor version, then simply:
Code:
git checkout stock-6.0.y
There's a twrp-6.0 branch that's used for building the kernel inside the official TWRP for Note 7 / S7 / S7 edge.
There's also a nethunter-6.0 branch used to build the kernel used by Kali NetHunter on those devices.
You can use git log <branch> to view commits, and git cherry-pick <commit id> to copy commits from those branches into yours if you like.
CONFIGURING GIT
Before you start working on your kernel, you will need to set up your git profile.
The user values show up in commit messages to tell people who authored them.
Code:
git config --global user.name "Your Name"
git config --global user.email "[email protected]"
git config --global push.default simple
YOUR FIRST COMMIT
We'll want to check out a new branch, and give it your own cool name. I suggest adding a -6.0 suffix to it because you'll probably want to start a new branch when Android 7.0 comes out.
We're going to use "coolname" as our example, so be sure to replace that with what you really want it to be called in the next steps.
Code:
git checkout -B coolname-6.0
Next we'll need to modify the build scripts to fit our setup.
Open build.sh, menuconfig.sh, and dtbgen.sh.
You'll want to set the TOOLCHAIN= path in all 3 scripts. If you're following this guide, then it's already correct!
In menuconfig.sh and build.sh, you'll want to set your default target config name.
See the line:
Code:
[ "$TARGET" ] || TARGET=samsung
You'll want it to look like this:
Code:
[ "$TARGET" ] || TARGET=coolname
Now you want to copy the default samsung kernel configuration so you have your own to work with:
Code:
cp arch/arm64/configs/samsung_defconfig arch/arm64/configs/coolname_defconfig
Now you'll have prepared your kernel source for starting work on your own custom kernel!
Let's turn that into a commit, but first look at the changes you've made using:
Code:
git diff
Does that look good? If not, fix what's broken before proceeding.
Next you'll want to add files that will be part of your commit.
For simplicity's sake, let's just add all of the changed files into the commit.
Code:
git add .
Now to make your commit:
Code:
git commit -m "My first commit, setting up my coolname kernel!"
You've done it!
CONFIGURING YOUR KERNEL
We'll use the menuconfig.sh script to launch the kernel menuconfig.
Code:
./menuconfig.sh
Change whatever options you're interested in, but don't change a lot all at once, otherwise when or if you run into issues, you won't know which option caused it.
Once you're done playing in the menuconfig, exit and save.
You'll be shown a colorful difference between your old configuration and your new one.
It will ask you if you want to save it, and you just have to type "y" and press enter for it to be saved.
At this point it's a good idea to make another commit to save your configuration changes.
If you need to edit the commit, you can easily use git commit --amend to fix it up.
BUILDING YOUR NEW KERNEL
Let's take your new config for a test drive.
To build your kernel, simply run:
Code:
./build.sh gracelte xx
gracelte = Note 7
herolte = S7
hero2lte = S7 edge
xx = International N930F & N930FD
kor = Korean N930K, N930L, & N930S
Yes, you can compile your kernel to all 3 of those devices using just your single config!
The power of device specific config additions.
Once your kernel is finished building, the resulting files will be located at:
Code:
build/arch/arm64/boot/Image
build/arch/arm64/boot/dtb.img
build/modules/*.ko (if modules are enabled)
INSTALLING YOUR NEW KERNEL
The LazyFlasher project comes to the rescue here. It's the swiss army knife of kernel flashing in TWRP.
There's a specific branch for the Note 7 called kernel-flasher-gracelte. (use kernel-flasher-herolte instead if building for S7/S7 edge!)
To download it (feel free to fork it so you can have a copy on your GitHub to modify instead!):
Code:
cd ~/build
git clone -b kernel-flasher-gracelte https://github.com/jcadduono/lazyflasher.git
cd lazyflasher
To use LazyFlasher, you'll probably want to take a look at the Makefile, config.sh, and META-INF/com/google/android/update-binary (a shell script).
There's a few things you can change there to personalize it to your needs.
You should also enter the patch.d folder and delete 060-f2fs-fstab if you don't have f2fs enabled in your kernel, and edit the io_scheduler in 070-kernel-settings if you don't have fiops enabled either.
(make another git commit to save your setup!)
Once the installer is set up to your liking, all you have to do to build it is copy the Image and dtb.img from your build output into the lazyflasher folder.
If you have any modules (.ko files) to install, place them in the modules folder.
Now simply run:
Code:
make
A TWRP flashable zip and sha1sum is created!
At this point, you will need to use the [Format Data] button in TWRP if your device is encrypted! There is no known way around this.
This will wipe all data from your phone, including your internal storage, essentially making it like new.
Transfer it to TWRP and flash away, you've just lost your custom kernel development virginity.
Go have a few beers to celebrate, or to drown your sorrows in the case of a boot loop.
You should consider taking a look at the patch.d scripts sometime so you know what it's actually doing.
PROBLEMS?
Post a reply here and I'll try to find a solution and add it to this post.
RESOURCES
Need a text editor for coding? I use gedit. It's pretty, light, and you can get some decent plugins for it.
It's a minimal editor, so don't expect anything really fancy. Configure it and enable plugins before you decide to trash it.
Code:
apt-get install gedit gedit-plugins
Here's an awesome git starter guide: http://rogerdudler.github.io/git-guide/
THANKS
If not for @Tkkg1994 finding out what changes are needed to get custom kernels up and running, we wouldn't have this lovely guide here!

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Thanks for the amazing guide, i got it compiled successfully but the problem comes after the device boots up, it asks for my Pattern and when i enter it, it keeps saying incorrect and wont let me in, any help?

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Ather said:
Thanks for the amazing guide, i got it compiled successfully but the problem comes after the device boots up, it asks for my Pattern and when i enter it, it keeps saying incorrect and wont let me in, any help?
Click to expand...
Click to collapse
Sorry, I forgot to add to the guide that custom kernels don't support encryption. You should flash your stock kernel & supersu, install something like titanium backup, and back up all your things to an external SDcard.
I've added a warning in the thread and included it in the instructions now.

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that's weird, I disabled lockscreen security and reinstalled the kernel, booted up fine with selinux enforcing http://i.imgur.com/IVSTfV1.png

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Ather said:
that's weird, I disabled lockscreen security and reinstalled the kernel, booted up fine with selinux enforcing http://i.imgur.com/IVSTfV1.png
Click to expand...
Click to collapse
Are you still encrypted?
Maybe it's just one of the secure mobicore firmware that were removed that your lock screen depended on. You might be able to set up the lock screen again now, and this time it won't require that specific piece of firmware.

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no i had already wiped data when i installed hydra kernel so after flashing my custom kernel i tried to setup the fingerprint and it gave an error that the fingerprint sensor isn't available try later, do you have any idea how to make a decrypted kernel like hydra?

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Ather said:
no i had already wiped data when i installed hydra kernel so after flashing my custom kernel i tried to setup the fingerprint and it gave an error that the fingerprint sensor isn't available try later, do you have any idea how to make a decrypted kernel like hydra?
Click to expand...
Click to collapse
Oh, I'm not sure why that happened then. There shouldn't have been anything extra removed on top of what HydraKernel removes.
My device is working with both Iris and Fingerprint unlock right now.
Can you post the output of:
Code:
ls /system/app/mcRegistry

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can you test out my kernel? i see hydra zip has some files that it replaces, and the lazyflasher has similar files, could that be the problem?

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Ather said:
can you test out my kernel? i see hydra zip has some files that it replaces, and the lazyflasher has similar files, could that be the problem?
Click to expand...
Click to collapse
try backing up your system/data to !!external sdcard!! in twrp, saving your internal storage to pc, then formatting data.
restore your stock kernel and system before flashing your custom kernel.
then see if it works from scratch.
if it's all fine, try restoring your data backup.

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Ather said:
no i had already wiped data when i installed hydra kernel so after flashing my custom kernel i tried to setup the fingerprint and it gave an error that the fingerprint sensor isn't available try later, do you have any idea how to make a decrypted kernel like hydra?
Click to expand...
Click to collapse
This sounds exactly like you did not patch /system/app/mcRegistry files
Sent from my SM-N930F using XDA Labs

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Tkkg1994 said:
This sounds exactly like you did not patch /system/app/mcRegistry files
Sent from my SM-N930F using XDA Labs
Click to expand...
Click to collapse
They shouldn't be patched though, the installer simply removes the secure ones that the device is unhappy with.
It works fine for me, so I know the offending ones are being removed, but maybe somehow it deleted all of his tlbins?
Be nice if he provided the contents of his mcRegistry :/

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jcadduono said:
They shouldn't be patched though, the installer simply removes the secure ones that the device is unhappy with.
It works fine for me, so I know the offending ones are being removed, but maybe somehow it deleted all of his tlbins?
Be nice if he provided the contents of his mcRegistry :/
Click to expand...
Click to collapse
Hello @jcadduono,
I am one of your "orphan" users of Idlekernel. It is the very best kernel for the Note 3.
Would you produce a blind update of it, please, please.
I would be more than happy to test it before you upload to general public.
Sorry guys for the OT.

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Need help for finalisation kernel
Hello and thank you OP for the tutorial, I have done everything and no worries except when I want to flash the kernel does not boot, then I would like to know how to get a boot.img with the dtb.img files and the image create after Compilation, if someone can help I will be grateful
Thank you

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Help on Kernel modules and patches
{MY QUESTIONS ARE ABOUT BOLD ITEMS BELOW}
Once your kernel is finished building, the resulting files will be located at:
Code:
build/arch/arm64/boot/Image
build/arch/arm64/boot/dtb.img
[B]build/modules/*.ko (if modules are enabled)[/B]
INSTALLING YOUR NEW KERNEL
The LazyFlasher project comes to the rescue here. It's the swiss army knife of kernel flashing in TWRP.
There's a specific branch for the Note 7 called kernel-flasher-gracelte. (use kernel-flasher-herolte instead if building for S7/S7 edge!)
To download it (feel free to fork it so you can have a copy on your GitHub to modify instead!):
Code:
cd ~/build
git clone -b kernel-flasher-gracelte https://github.com/jcadduono/lazyflasher.git
cd lazyflasher
To use LazyFlasher, you'll probably want to take a look at the Makefile, config.sh, and META-INF/com/google/android/update-binary (a shell script).
There's a few things you can change there to personalize it to your needs.
You should also enter the patch.d folder and delete 060-f2fs-fstab if you don't have f2fs enabled in your kernel, and edit the io_scheduler in 070-kernel-settings if you don't have fiops enabled either.
(make another git commit to save your setup!)
Once the installer is set up to your liking, all you have to do to build it is copy the Image and dtb.img from your build output into the lazyflasher folder.
If you have any modules (.ko files) to install, place them in the modules folder.
Now simply run:
Code:
make
Got a few question for anyone that is familiar with the exynos8890-gracelte BUILD. This in regards to files output after compilation of kernel code; specifically with editing patches and providing module support.
Where are the *.ko files located if default output is used(using your ./build.sh gracelte xx)? By the way...Your tutorial is awesome, first and foremost...but I want to be sure that I am pulling the files from the correct location (being a newbie at this android kernel building stuff). I found my modules under "~/build/kernel/samsung_universal8890/build/lib/modules/3.18.14-dee-gracelte-xx-0.1" which is the parent folder to other folders/files that seem to be of interest. After digging deeper there are even folders within the previously mentioned (named) one that have items of question as to whether they are needed in my "flasher" module folder. Such as pictured https://drive.google.com/open?id=0B-3GHX6_T7lYRkRUUVVORE1OM1k
I just want to have a functioning kernel with module support/modules in there proper place. Another item is patches. Would it be possible to just change "070-kernel-settings" patch to "io_scheduler=noop" if I changed default setting to such? If so, what other, if any, items in this file would need editing? Where else can I find patch files located on the web or is this something home-brewed? Thanks for all your hard work.

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I also assume that by changing to the proper package manager commands, this procedure will work for pretty much most Linux distros.
Windows 10 Support Number