Develop Bugs

[PATCH] Kexec-hardboot patch

In this post, I would like to explain what kexec-hardboot patch is.
@kernel developers: I would like to ask you to merge this patch to your kernels, because it is essential part of MultiROM - it allows me to boot any kernel without changing the boot partition. I realize that it is no small request, but the patch is not big, touches relatively stable parts of kernel and should not cause any problems. Thank you.
What is kexec?
It is syscall of Linux kernel, which allows you to boot another Linux kernel without restarting the device - "Linux boots itself". The functionality is equivalent to fastboot -c *cmdline* boot zImage initrd.img, but without PC and fastboot. It is fairly known thing, so more info at wikipedia and man kexec.
Standard kexec call unfortunatelly does not work on Nexus 4. It freezes somewhere, and it is very difficult to find out where - probably some of the drivers are not shut down/re-initialized properly, it is a commong thing among Android devices, which is why kexec-hardboot was made.
What is the difference between normal and hardboot exec?
Kexec-hardboot patch adds a real device restart to that process, so that all the drivers can be properly reinitialized. It stores new kernel to RAM, reboots the device as usual, and kernel from boot partition immediately jumps to the one which was stored to RAM before reboot.
Unlike grouper's kexec-hardboot patch, this one only requires the host kernel to be patched. This is one of the improvements I made, and I think it is pretty significant.
To sumarize the process:
kexec --load-hardboot.... is called and kernel it loaded into RAM.
kexec -e is called. Special info is written to memory (to area which is not overwritten on reboot) and the device is rebooted.
After reboot, very early in the boot process, kernel checks if that special info is present in RAM and if so, it loads new kernel from RAM and jumps to it.
Kexecd' kernel starts and boots.
For more info, read the original thread.
Patches:
Kernel patch: https://gist.github.com/Tasssadar/7833796, 4.4 AOSP kernel repo
This is the kernel patch. Only the host kernel needs to be patched.
Related CONFIG options:
CONFIG_KEXEC=y
CONFIG_KEXEC_HARDBOOT=y
CONFIG_PROC_DEVICETREE=y
CONFIG_ATAGS_PROC=n # This one is turned on automatically, but it is not needed, so you can disable it.
All these options must be enabled.​
Userspace kexec binary: https://github.com/Tasssadar/kexec-tools
I had to change some things in kexec userspace binary because of some kernel bugs, complete description is in that repository. You can get statically built binary at https://github.com/Tasssadar/multirom/blob/master/install_zip/prebuilt-installer/multirom/kexec​
Usage:
Once you have the kernel patches and kexec userspace binary in place, just run following command to boot into new kernel:
Code:
kexec --load-hardboot zImage --initrd=initrd.img --mem-min=0x20000000 --command-line="$(cat /proc/cmdline)" --dtb
kexec -e
Note the command line parameter - cmdline from bootloader is not added automatically, you have to put it there by yourself.
Authors:
This patch was made by Mike Kasick for Samsung Epic 4G. Since that, it was ported to several devices, one of them is Asus Transformer TF201 - I used patch from TF201 and modified it a bit (basically just changed few SoC specific constants). People at #ubuntu-arm helped me out with that, thanks.
For hammerhead, I've improved the patch a bit - only the host needs to be patched now and I've added support for DTB.

Merged, thanks again for the awesome work @Tasssadar!

Good deal.My day is getting better.

@show-p1984 would love to see this in bricked kernel too! ?

@neobuddy89 did you see this?
Sent from Nexus 5 on Slimkat

thanks for the hard work.. thats awesome.

AndroidSlave said:
@neobuddy89 did you see this?
Sent from Nexus 5 on Slimkat
Click to expand...
Click to collapse
Yeah, I saw this.

neobuddy89 said:
Yeah, I saw this.
Click to expand...
Click to collapse
I asked that 6 months ago
Sent from my Nexus 5 using Tapatalk

awesome work bro...
much needed..

AndroidSlave said:
I asked that 6 months ago
Sent from my Nexus 5 using Tapatalk
Click to expand...
Click to collapse
Yeah, I know and I saw that days back..
Enough of OT. :fingers-crossed:

Help with applying the patch
Okay so I have my aosp kernel made. I have my working directory too. Can you just guide me on how do I apply this partch to it?

Is it possible to add that patch from a on the fly flashable zip ?

@Anoopnk since the patch is for the kernel(zImage) its not possible to patch it like that. Or you have to compile the kernel or you need to ask your kernel dev friendly or he can include it in his kernel.

Hello, first I'd like to apologize for dredging up an old thread. Second, I am attempting to build a CM13+kali+kexec compatible kernel, with extra wifi drivers as the base kernel doesnt support my wifi card. Based on that goal, I have a multi-part question for the OP, or anyone else with the know-how to assist me in my quest.
1)Is there a source available for your kernel_kexec_hammerhead_cm13-01-2c39db662.zip listed on the multirom page for nexus 5? I'm attempting to build a new kernel, for kali+CM13+multirom, and your android_kernel_google_msm git only has branches going up to CM12. It would be far easier for me to start with a 'clean' CM13+kexec source then trying to patch myself as per question #2
2) I've attempted to patch a plain old hammerhead_defconfig from CM13 git, however I believe I am doing so wrong. I have managed to compile kexec-tools and aquired the hammerhead 3.4.x patch. Now am I supposed to patch my produced zImage-dtb AFTER build, running the patch from the kexec-tools folder and against the zImage-dtb? Is it something like 'KEXEC.patch -p1 < zimage-dtb'
Any clarification on the use of the kexec-tools patch, or simply a link to github source of a 'clean' CM13 kernel with the kexec patch already applied, would be incredibly helpfull on my journey down the rabbit hole
~EDIT~
Ok so I've managed to figure out the patch and feel like a dumbass. For anyone else looking to get into kernel dev, and wanting to use the kexec patch, heres the basics:
1- run patch within your kernel source directory
2-ensure that the config settings in OP are set (I had to add them to my source by hand as they werent there)
3-when zipping up your kernel, add the sbin and lib/kexec-tools folders from the kexec-tools source build, and be sure your updater-script / updater-binary is set to move these folders into /sbin and /lib respectively.
4-Flash and enjoy Kexec! (check with multirom manager)

[kernel][custom][P905] permiisive with init.d support 06/02/2016

hi guys
i finally was able to make a custom kernel with permissive selinux
it seems that my previous roms were having some missing files thats why the kernel did not function well with them
anyway, now it is working properly and so far no problems
i already included the V1 in my rom
so i made a different thread so that it will not be confusing
changelog:
V1: initial release
permissive selinux
V2: 06/02/2016
added init.d support
links to the kernel
mediafire
http://www.mediafire.com/download/l6cuhlevy799l8g/Teflanzy_Kernel_P905XXUABOL2_V2.zip
google drive
https://drive.google.com/file/d/0B_-JMtGLOAd3LU9pRS1iUXhKdGc/view?usp=sharing
MD5 checksum: E958AAD584A25FFB395249CDF8A7D116
kernel source on github
https://github.com/Teflanzy/viennalte_p905_kernel_source
kernel ramdisk with init.d support on github
https://github.com/Teflanzy/viennalte_p905_kernel_ramdisk
use this program from @osm0sis for create boot.img from ramdisk and zimage
http://forum.xda-developers.com/showthread.php?t=2073775
please report back with any problems you are facing

Glad to be the first to thank you for your great job @Teflanzy ?
Really happy to see the P905 getting the attention it deserves!

ADM!RAL said:
Glad to be the first to thank you for your great job @Teflanzy
Really happy to see the P905 getting the attention it deserves!
Click to expand...
Click to collapse
thanks for your reply
but do not expect much from me
I am just a beginner and wanted a permissive kernel for my device
I will try to add more features but it might take a long time for me to apply them

Teflanzy said:
thanks for your reply
but do not expect much from me [emoji14]
I am just a beginner and wanted a permissive kernel for my device
I will try to add more features but it might take a long time for me to apply them
Click to expand...
Click to collapse
Great things don't have to be big and bulky bro [emoji4]
I made a post when i first bought the device asked how to make rom deodexed so xposed could be installed and how hard is the process!!
What I'm trying to say is we just wanted the simplest of things [ofc i don't mean it's easy but things that are straight to the point]
Your kernel is just doing that [emoji111]
Opens the door to further mods!
Best of luck bro [emoji106]

Thank you very much for your work, I'll try.

Hello. First, I wanted to thank you for a job well done!
I am using the kernel for something like one and half a month with KOKO ROM and it is *stable*. And I mean stable as hell! - I don't remember even a single random reboot so far! Of course, switching selinux mode with setenforce command is working like a charm, as well as init.d support. Great, great job!
I personally find P905 (and probably other qcom-based variants) *still* the best tablet on the market so far (in my opinion, ofc ).
I am also really *not* interested in custom CM13 developement as stock ROMs has far more Sammy's specific features like *stable* MultiWindow support or S-Pen stuff and even if it is a good experience, I still find using it a waste of device's potential...
That is why I was personally thinking about adding some most popular custom features, like smartmax governor (which I personally find the best option for Snapdragon 800 devices, but opinions may vary ofc...), some custom hotplug driver (MPDecision sucks...) and first of all - enabling CPU overclock/undervolt (I find default maximum horsepower a little too short for handling more advanced tasks on this awesome but resource-hungry QHD screen; also battery-life is not as awesome as it was two years ago...).
So, I wanted to ask you if you are considering further developement of this stock-based kernel?
Also, if you don't have time/will/attitude to continue this great job, I wanted to ask if you have released any sources on github or something which one may sync and continue the developement?
Thank you in advance for the answer.
Best regards.

esgie said:
Hello. First, I wanted to thank you for a job well done!
I am using the kernel for something like one and half a month with KOKO ROM and it is *stable*. And I mean stable as hell! - I don't remember even a single random reboot so far! Of course, switching selinux mode with setenforce command is working like a charm, as well as init.d support. Great, great job!
I personally find P905 (and probably other qcom-based variants) *still* the best tablet on the market so far (in my opinion, ofc ).
I am also really *not* interested in custom CM13 developement as stock ROMs has far more Sammy's specific features like *stable* MultiWindow support or S-Pen stuff and even if it is a good experience, I still find using it a waste of device's potential...
That is why I was personally thinking about adding some most popular custom features, like smartmax governor (which I personally find the best option for Snapdragon 800 devices, but opinions may vary ofc...), some custom hotplug driver (MPDecision sucks...) and first of all - enabling CPU overclock/undervolt (I find default maximum horsepower a little too short for handling more advanced tasks on this awesome but resource-hungry QHD screen; also battery-life is not as awesome as it was two years ago...).
So, I wanted to ask you if you are considering further developement of this stock-based kernel?
Also, if you don't have time/will/attitude to continue this great job, I wanted to ask if you have released any sources on github or something which one may sync and continue the developement?
Thank you in advance for the answer.
Best regards.
Click to expand...
Click to collapse
Thanks for your words
As i said before
I am a beginner so i do not know how to add the features like other governors or enabling volt control
Furthermore i deleted my source but i can remake it because there are small changes that i made and i remember them
I am currently trying to port features from other snapdragon 800 devices kernels like note 3 and note 10.1 2014 edition
But i still get error on compiling
I will prepare the github source then post a link for it

@esgie
i just uploaded the kernel source with ramdisk each in seperate link
hope it is useful to you
i need help with adding synapse support to the kernel
if you know how to do let me know

Thank you.
I have just configured my developement environment.
I will try to proceed with compilation this weekend. I will also check how to implement synapse support
Hear you soon.

Hi.
I want you to know that I am absolute kernel-beginner, too.
Anyway, I have managed to add some basic features to the kernel.
Here you can download img file and test:
https://drive.google.com/folderview?id=0B2TnsPjj6dl4dHNZN3dBb3o1Zlk&usp=sharing
(as of TWRP 3 img files can be flashed directly to boot partition from recovery; P905 only!!!).
Features:
- setenforce working + init.d support (by Teflanzy)
- some custom schedulers (bfq, fiops, sio)
- custom governor (zzmoove with hotplugging support - I recommend to tune it with Kernel Adiutor using profile_number = 5, disable_hotplug = 0 and disabling mpdecision).
So not much at the moment.
It looks like it's hard to automatically cherry-pick a lot of interesting CM12-compatibile commits, as the samsung kernel source differs a lot from the CM one... I failed to add synapse support as for now but I am looking into the issue. Also, I will post and sync my sources not later than tomorrow.
Sorry, my time is limited and experience is not very big.
I am posting a test version here and if there will be enough feedback we may think about creating a separate topic and try to start some constant developement
Sources:
https://github.com/esgie/viennalte_p905_kernel_source

esgie said:
Hi.
I want you to know that I am absolute kernel-beginner, too.
Anyway, I have managed to add some basic features to the kernel.
Here you can download img file and test:
https://drive.google.com/folderview?id=0B2TnsPjj6dl4dHNZN3dBb3o1Zlk&usp=sharing
(as of TWRP 3 img files can be flashed directly to boot partition from recovery; P905 only!!!).
Features:
- setenforce working + init.d support (by Teflanzy)
- some custom schedulers (bfq, fiops, sio)
- custom governor (zzmoove with hotplugging support - I recommend to tune it with Kernel Adiutor using profile_number = 5, disable_hotplug = 0 and disabling mpdecision).
So not much at the moment.
It looks like it's hard to automatically cherry-pick a lot of interesting CM12-compatibile commits, as the samsung kernel source differs a lot from the CM one... I failed to add synapse support as for now but I am looking into the issue. Also, I will post and sync my sources not later than tomorrow.
Sorry, my time is limited and experience is not very big.
I am posting a test version here and if there will be enough feedback we may think about creating a separate topic and try to start some constant developement
Sources:
https://github.com/esgie/viennalte_p905_kernel_source
Click to expand...
Click to collapse
nice work
now I can check your commits and understand how to add extra governors
gonna download your version and test and report back after usage for a couple of days

[DEVONLY] LineageOS 15

Hi,
this is the development thread for LineageOS development. The first release is out and this thread is for developer collaboration!
Everyone who knows C, Java and strace is welcome to participate. Please send git formatted patches!
HELP NEEDED
mixer_paths_tasha.xml and audio_platform_info.xml need tweaking
VoIP needs testing
WifiDisplay support
VoLTE (I can't test this)
Device Trees
https://github.com/cryptomilk/android_kernel_sony_msm8998
https://github.com/cryptomilk/android_device_sony_common-treble
https://github.com/cryptomilk/android_device_sony_yoshino
https://github.com/cryptomilk/android_device_sony_lilac

What about the bootloader?

blackknightavalon said:
What about the bootloader?
Click to expand...
Click to collapse
Just unlock it and have fun. Hopefully someone will be able to figure out a way to backup the DRM keys.

android_fury said:
Just unlock it and have fun. Hopefully someone will be able to figure out a way to backup the DRM keys.
Click to expand...
Click to collapse
And where, exactly, is the tutorial for that? It's not officially supported by Sony yet.

I think I read somewhere that you can select the XZ Premium on the list and follow the steps. Once a DRM backup is available, I may try doing that. By then, the actual XZ1C may already be on the list.

android_fury said:
I think I read somewhere that you can select the XZ Premium on the list and follow the steps. Once a DRM backup is available, I may try doing that. By then, the actual XZ1C may already be on the list.
Click to expand...
Click to collapse
I just checked a few minutes ago. XZ1C's not on there.

Good news ！

I've setup initial repositories, yoshino and lilac. yoshino is a common base shared between devices and I have a Kernel tree over the latest msm-4.0 kernel tree and already compiled it after fixing a log of build issues. I will create repositories in the next days and upload the sources once I have a recovery.

modpunk said:
I've setup initial repositories, yoshino and lilac. yoshino is a common base shared between devices and I have a Kernel tree over the latest msm-4.0 kernel tree and already compiled it after fixing a log of build issues. I will create repositories in the next days and upload the sources once I have a recovery.
Click to expand...
Click to collapse
Great news! Thank you so much for your efforts to bring us LOS for this really awesome compact beast.

Thank you so far, modpunk! Looking forward to it. The phone is great, but stock rom leaves some things to be desired...

Thanks bro, just do it!

Regarding unlocking: I selected X Compact and followed the instructions. Everything worked perfectly and I'm now running AOSP.

Code:
----- Made recovery image: recovery.img --------
#### make completed successfully (11:06 (mm:ss)) ####

modpunk said:
I've setup initial repositories, yoshino and lilac. yoshino is a common base shared between devices and I have a Kernel tree over the latest msm-4.0 kernel tree and already compiled it after fixing a log of build issues. I will create repositories in the next days and upload the sources once I have a recovery.
Click to expand...
Click to collapse
How much are you borrowing from Sony's AOSP repositories? They've been committing pretty heavily to their kernel in particular.

Gairtial said:
How much are you borrowing from Sony's AOSP repositories? They've been committing pretty heavily to their kernel in particular.
Click to expand...
Click to collapse
There was no Kernel release for msm8998 in kernel-copyleft, so I took the msm-4.4 Kernel tree and the tarball they dropped. I've fixed several bugs in the Kernel, I always wonder how the Smartphone manufacturers get their stuff compiled.
You can find the kernel source tree here: https://github.com/cryptomilk/android_kernel_sony_msm8998
I've also added exfat support already.
I've looked at the device repo for their AOSP trees, but started a yoshino and lilac device tree from scratch. I prefer clean repositories. I will push them in the next days, I did quite some cleanup today.
I haven't ordered the device yet. Need to wait till next week, I just came back from a long vacation

modpunk said:
There was no Kernel release for msm8998 in kernel-copyleft, so I took the msm-4.4 Kernel tree and the tarball they dropped. I've fixed several bugs in the Kernel, I always wonder how the Smartphone manufacturers get their stuff compiled.
You can find the kernel source tree here: https://github.com/cryptomilk/android_kernel_sony_msm8998
I've also added exfat support already.
I've looked at the device repo for their AOSP trees, but started a yoshino and lilac device tree from scratch. I prefer clean repositories. I will push them in the next days, I did quite some cleanup today.
I haven't ordered the device yet. Need to wait till next week, I just came back from a long vacation
Click to expand...
Click to collapse
Why the copyleft archive? It doesn't look like they've touched it since April while they touched the regular one 2 hours ago.
I had no issues compiling and running the kernel from https://github.com/sonyxperiadev/kernel, though that was integrated with their entire AOSP tree, which seems to package its own versions of gcc and clang. Perhaps LineageOS includes different prebuilt compilers and that's why you see issues.
Really curious to see how LOS runs though. AOSP has some annoying performance issues and crashes.

Gairtial said:
Why the copyleft archive? It doesn't look like they've touched it since April while they touched the regular one 2 hours ago.
I had no issues compiling and running the kernel from https://github.com/sonyxperiadev/kernel, though that was integrated with their entire AOSP tree, which seems to package its own versions of gcc and clang. Perhaps LineageOS includes different prebuilt compilers and that's why you see issues.
Really curious to see how LOS runs though. AOSP has some annoying performance issues and crashes.
Click to expand...
Click to collapse
I've just tried to build the aosp/LA.UM.5.7.r1 tree from the sony kernel repo. This one has a lot of compiler errors which need fixing first. However for me it looks like that the msm-4.4 tree is much cleaner in this regard so maybe also more advanced.

modpunk said:
I've just tried to build the aosp/LA.UM.5.7.r1 tree from the sony kernel repo. This one has a lot of compiler errors which need fixing first. However for me it looks like that the msm-4.4 tree is much cleaner in this regard so maybe also more advanced.
Click to expand...
Click to collapse
Also fellow LineageOS developers said that the sony 'kernel' repo is a Proof of Concept repo and not what they use in production. So I stick to the production release of MSM.

modpunk said:
I've just tried to build the aosp/LA.UM.5.7.r1 tree from the sony kernel repo. This one has a lot of compiler errors which need fixing first. However for me it looks like that the msm-4.4 tree is much cleaner in this regard so maybe also more advanced.
Click to expand...
Click to collapse
Huh, what kinds of errors are you seeing? I really suspect it must be something different between LOS and AOSP and I'm wondering what it is.
modpunk said:
Also fellow LineageOS developers said that the sony 'kernel' repo is a Proof of Concept repo and not what they use in production. So I stick to the production release of MSM.
Click to expand...
Click to collapse
This may be true but it's also the repo where the most work is done. We should at least pay attention to it in case they commit fixes that are useful.
Also probably getting ahead of myself but I wonder if we can merge EAS... It's in AOSP's common kernel, is it around in LOS anywhere yet?

Gairtial said:
Huh, what kinds of errors are you seeing? I really suspect it must be something different between LOS and AOSP and I'm wondering what it is.
This may be true but it's also the repo where the most work is done. We should at least pay attention to it in case they commit fixes that are useful.
Also probably getting ahead of myself but I wonder if we can merge EAS... It's in AOSP's common kernel, is it around in LOS anywhere yet?
Click to expand...
Click to collapse
You get the errors with -Wmaybe-uninitialized which is a relatively new gcc feature. The Sony 'kernel' repo is their Proof of Concept repository. Yes, sure they are working on it it makes totally sense to try things out there first!
I dunno what EAS is or means ...

[KERNEL][OREO] [SM-T830/T835] [2019-11-21] Modesty 1.0.0 [Linux 4.4.202] [ARK4]

Modesty - a modest custom kernel for the Samsung Tab S4
Modesty aims to provide a mildly appealing and reasonable alternative to the stock 4.4.78 kernel that comes with The Tab S4. In its pursuit of being both mildly appealing and reasonable, it will eschew features that could compromise device stability, whilst gleefully embracing low-risk, self-contained enhancements. In other words, your lowest expectation should be that this kernel will be at least as stable as the stock kernel.
Since there are currently no other custom kernel projects supporting the Tab S4, there isn't really any previous device-specific work to build on. Development of this kernel is therefore likely to be slow and steady.
"Why is this kernel called Modesty? That's crap! Why not Wolverine, Intrepid or Jupiter?"
Because it's just a operating-system kernel, not a turbo-charged supercar or a mission into outer space. Even as operating-system kernels go, this one is pretty dull. Besides, I'm a weary curmudgeon in his fifties, not a teenager.
This project has the modest aim of modestly enhancing the pleasure you derive from your Tab S4 and is therefore modestly named Modesty.
Key characteristics
Supports both the wi-fi only (T830) and wi-fi/LTE (T835) models.
Forked from Samsung's pristine kernel source code (Linux 4.4.78 for ARGH firmware at time of launch).
Regular merging of the upstream Linux kernel's linux-4.4.y branch (4.4.161 at time of public launch).
Regular merging of Samsung's updates to its modified kernel source as they are made available.
Includes @savoca's KCAL advanced colour/gamma control driver.
Includes @flar2's sound control driver to manage headphone and microphone gain.
Disables a huge amount of tracing and logging features inexplicably left enabled by Samsung in the stock release kernel. These debugging features have no place outside engineering builds.
Packed into a boot.img (boot image) taken directly from Samsung's latest stock firmware and kept as close to the original as possible. No obscure boot-time kernel configuration is stashed away here, and no changes are made to any other part of the file system at either install time or run time.
Provides a fully automated installer, with the option of interactive installation to allow manual selection of features and the ability to automatically root the device with Magisk in the post-installation phase.
Includes WireGuard VPN support (version 0.0.20180818 at the time of public launch), which will be updated as available.
Includes @Lord Boeffla's generic kernel wakelock blocker. The conservative default block-list is: qcom_rx_wakelock and NETLINK.
Utilises Westwood+ TCP congestion algorithm by default.
Includes Veno TCP congestion algorithm.
SELinux operates in enforcing mode and cannot be dynamically switched to permissive mode.
FAQ
Q. Is this kernel still actively developed?
A. No. The final ianmacd release was v1.0.0 on 21st November 2019 and no-one else has picked up maintenance of the project.​
Q. Will this kernel also run on Android 9.0 (Pie) devices?
A. No. Modesty targets Android 8.1 (Oreo) and there was never an intention to update it for 9.0 (Pie).​
Q. Can I overclock or underclock the CPU using this kernel?
A. No.​
Q. How does interactive installation mode work?
A. If the ZIP file name contains the string _interactive or a dot-file called .modesty_interactive is present in the root of the external SD card, interactive installation mode is triggered. Please note that this mode overrides any selections implied by the archive name or the presence of dot-files on the file-system.
In interactive mode, you will be asked whether to root the device afterwards with Magisk. Selections are made using the Volume buttons. Just follow the on-screen prompts.​
Q. Can I safely block wakelock X?
A. Perhaps. However, unless you know what a particular wakelock does and are certain that it is causing an actual problem on your device, I suggest you leave it alone.​
Q. Why is this kernel labelled beta? Is it safe to use? And who are you, anyway? Can you be trusted?
A. My T830 has been running this kernel every day since I first rooted it, and I can therefore personally vouch for its stability on this model.
A couple of users have reported Modesty running well on the T835. Initially, it was reported that the kernel did not boot on this model, but after trying several test kernels, the user in question discovered that his machine had a non-standard firmware installation. Once this situation was remedied, Modesty booted and worked as designed.
As the person who built the kernel, I know exactly what's in it, and therefore the only risk I'm exposing myself to when I run it is that of my own incompetence. That's not true for you, however, and you should exercise due caution and at least pause for a moment to consider what you are installing, and the far-reaching powers you are about to grant this unaudited code over your device. Although I link to the source code below, you have only my word for it that this bears any resemblance to the kernel actually provided in the installer.
There are likely to be many iterations of this kernel before it sees a 1.0 release. Features may be added or removed along the way, although there is no clear roadmap at this point in time. Development will go where the needs of the users take it.
Please see the Installation section below for an important note regarding the use of this kernel in combination with stock (i.e. unmodified) Samsung firmware.​
Q. Can I safely root this kernel?
A. Of course. What use would it be if you couldn't? I recommend Magisk for the task. It has a few minor issues, but as a project is very much alive, something that cannot be said about its peers. Magisk has arguably now established itself as the de facto root solution for Android devices.
It just so happens that I also produce my own builds of Magisk, which you are welcome to use. These are release builds (as opposed to debugging builds), produced from my own fork of @topjohnwu's original source, often augmented with patches. You can use anyone's builds, though.
Again, these builds work for me on various Samsung devices, but they are unofficial and you should approach them with fitting caution.​
Q. Can I install Magisk at the same time as Modesty?
A. Yes. The Modesty installer allows you to automatically root your device with Magisk following installation of Modesty..
To make use of this facility, either rename the Modesty zip file to contain the string _magisk or create a file called .modesty_magisk in either the root of your external SD card or in the standard Download directory of the internal SD card. Alternatively, you can utilise interactive installation mode. See above for details.
If any of these trigger conditions is met, the installer will look in the standard internal Download directory as well as in ./Magisk (if present) on the external SD card (if present) for a suitable Magisk zip file to install. Preference is given to versioned files matching the glob Magisk-v*, in which case the latest according to lexical sort order will be used. If none is found, the installer then looks for unversioned release builds (e.g. official Canary channel release builds) called magisk-release.zip in the same locations, selecting the one with the most recent timestamp. If none is found, the installer will then try to find unversioned debug builds (e.g. official Canary channel debug builds) called magisk-debug.zip, again picking the one with the most recent timestamp. Finally, the installer falls back to looking for the most recent file called Magisk.zip or magisk.zip. If still no files have been found by this stage, chaining of Magisk is abandoned.
For example:
Code:
star2lte:/ $ ls -l /storage/0000-0000/.modesty_magisk
-rwxrwx--x 1 root sdcard_rw 0 2018-09-15 14:31 /storage/0000-0000/.modesty_magisk
star2lte:/ $ ls /storage/0000-0000/Magisk/Magisk-* | tail -n 3
/storage/0000-0000/Magisk/Magisk-v17.2-2018091001-ianmacd.zip
/storage/0000-0000/Magisk/Magisk-v17.2-2018091201-ianmacd.zip
/storage/0000-0000/Magisk/Magisk-v17.2-2018091501-ianmacd.zip
When you flash the Modesty archive in TWRP, the most recent version of Magisk that could be found will now be used to automatically root your kernel, i.e. Magisk-v17.2-2018091501-ianmacd.zip in this example.​
Q. Why doesn't Modesty have its own Telegram group?
A. Because my experience of Android-themed Telegram groups is that they invariably degenerate into seething cesspits of rudeness, ignorance, superstition and — on a good day — pseudo-science. I don't wish to police such a den of iniquity. Of course, it's a free world (or so I still like to kid myself), so you are at liberty to create your own Telegram group for Modesty if you wish. Just please don't invite me to it.​
Building
Building the kernel from source is beyond the scope of this document. If you want to build this kernel from scratch, for example to change its configuration, start with this handy reference tailored to building kernels for Android.
Download
See posting #2 in this thread for links to the latest and all previous versions.
Known Issues
Bluetooth HID (input) devices do not work.
Versions 0.99.11 to 0.99.22 contained a bug that caused Bluetooth HID (input) devices, such as mice, keyboards and gamepads, not to function. They could be paired with the tablet, but their input was not recognised. This bug was finally traced and fixed in 0.99.23.​
Installation
Make a back-up of your existing boot partition using the custom recovery environment provided by TWRP. If your device doesn't yet have TWRP, you will need to install it first. Then, use it to flash the Modesty ZIP file. The boot image will automatically be installed in the boot partition of your device.
If your device has unmodified Samsung firmware, you will encounter problems with Bluetooth (namely delayed initialisation and forgotten pairings) after installing this or any other custom kernel. To remedy this, you will need to patch your system with modified libsecure_storage.so libraries. Some custom kernel installers actually install these without telling you, overwriting your system libraries and transparently circumventing the problem before you can run into it. This approach necessarily modifies your device's file-system, however, and that may not be what you want. At the very least, the user should be made aware what is happening to his device.
For this reason, I have instead prepared a companion Magisk module that achieves the same goal without modifying the file-system. This will allow you to run a custom kernel (not just this one, but any custom kernel) on pristine stock firmware without any Bluetooth issues. The module can be found in the official Magisk module repository, accessible from Magisk Manager on your tablet. If you install this Magisk module, you may wish to also disable the secure_storage_daemon by editing /system/etc/init/secure_storage_daemon.rc (change start to stop), as it no longer serves a purpose.
In a similar vein, you may encounter authentication errors when connecting to wireless networks after installing this or any other custom kernel. This problem is not serious and easily remedied by re-entering your passphrase for the networks you use.
Finally, if SecurityLogAgent notifies you that unauthorised actions have been detected, do not be alarmed. This is a normal consequence of having installed a custom kernel. You may wish to disable SecurityLogAgent to avoid being repeatedly notified..
Whilst the above issues are the only ones you can expect to encounter when running this kernel vs. the stock Samsung kernel, they may sound like more trouble than they're worth. In that case, you might be happier just sticking to Samsung's stock kernel. The company supplies a perfectly good kernel straight from the factory.
Configuration
You are encouraged to use either @morogoku's excellent MTweaks (a modified version of Kernel Aduitor) or @flar2's EX Kernel Manager to manage the features provided by this kernel.
Source code
Modesty's GitHub repository.
References
A useful guide to CPU governors, I/O schedulers (and more).
For more information on the some of the individual schedulers included in this kernel, you can also look under Documentation/block in the kernel source.
The WireGuard user guide, control app, home page and source code.
Credits
Thank you to everyone in the Linux kernel universe for getting us this far. Within the Android development community, I am grateful to the following people for their time-saving contributions:
@osm0sis for Android Image Kitchen, which has saved me a huge amount of work in packing and unpacking boot images.
An honorary mention must go to @Chainfire, the extent of whose benefaction to the Android community is still not fully understood or appreciated in some quarters.

Change log
v1.0.0 (final ianmacd release) (2019-11-21)
Kernel proclaimed stable. Version number incremented. No code changes since v0.99.49.
v0.99.49 (2019-11-16)
Updated to Linux 4.4.202.
v0.99.48 (2019-11-13)
Updated to Linux 4.4.201.
v0.99.47 (2019-11-11)
Updated to Linux 4.4.200.
v0.99.46 (2019-11-06)
Updated to Linux 4.4.199.
v0.99.45 (2019-10-31)
Updated to Linux 4.4.198.
v0.99.44 (2019-10-19)
Updated to Linux 4.4.197.
v0.99.43 (2019-10-08)
Updated to Linux 4.4.196.
v0.99.42 (2019-10-07)
Updated to Linux 4.4.195.
v0.99.41 (2019-09-22)
Updated to Linux 4.4.194.
v0.99.40 (2019-09-16)
Updated to Linux 4.4.193.
v0.99.39 (2019-09-11)
Updated to Linux 4.4.192.
Fixes unavailability of external SD card in Modesty 0.99.38.
v0.99.38 (2019-09-08) Release withdrawn (External SD card unavailable)
Updated to Linux 4.4.191.
v0.99.37 (2019-08-26)
Updated to Linux 4.4.190.
v0.99.36 (2019-08-12)
Updated to Linux 4.4.189.
v0.99.35 (2019-08-07)
Updated to Linux 4.4.188.
v0.99.34 (2019-08-05)
Updated to Linux 4.4.187.
v0.99.33 (2019-07-23)
Updated to Linux 4.4.186.
v0.99.32 (2019-07-12)
Updated to Linux 4.4.185.
v0.99.31 (2019-06-28)
Updated to Linux 4.4.184.
v0.99.30 (2019-06-22)
Updated to Linux 4.4.183.
v0.99.29 (2019-06-18)
Updated to Linux 4.4.182.
v0.99.28 (2019-06-12)
Updated to Linux 4.4.181.
v0.99.27 (2019-05-17)
Updated to Linux 4.4.180.
v0.99.26 (2019-04-28)
Updated to Linux 4.4.179.
v0.99.25 (2019-04-07)
Updated to Linux 4.4.178.
v0.99.24 (2019-03-26)
Updated to Linux 4.4.177.
Build only the latest revision of the DTB.
v0.99.23 (2019-03-02)
Fixed bug, introduced in v0.99.11, that caused input from Bluetooth HID devices, such as keyboards, mice and gamepads to be ignored.
v0.99.22 (2019-02-23)
Updated to Linux 4.4.176.
v0.99.21 (2019-02-20)
Updated to Linux 4.4.175.
v0.99.20 (2019-02-11)
Updated to Linux 4.4.174.
v0.99.19 (2019-02-08)
Updated to Linux 4.4.173.
v0.99.18 (2019-01-26)
Updated to Linux 4.4.172.
v0.99.17 (2019-01-17)
Updated to Linux 4.4.171.
v0.99.16 (2019-01-13)
Updated to Linux 4.4.170.
v0.99.15 (2018-12-30)
Rebased on ARK4 kernel source code and boot images.
v0.99.14 (2018-12-23)
Updated to Linux 4.4.169.
Merged four more UPSTREAM commits from android-4.4 kernel branch.
v0.99.13 (2018-12-13)
Updated to Linux 4.4.167.
Merged selected BACKPORT and UPSTREAM commits from android-4.4 kernel branch.
v0.99.12 (2018-12-05)
Updated to Linux 4.4.166.
Realtek USB Ethernet driver upgraded from v2.08.0 to v2.10.00.
v0.99.11 (2018-11-29)
Updated to Linux 4.4.165.
KCAL advanced colour/gamma control driver optimisation.
Added @flar2's sound control driver for controlling headphone and microphone gain. (Configure with MTweaks or EX Kernel Manager).
v0.99.10 (2018-11-21)
Updated to Linux 4.4.164.
Added KCAL advanced colour/gamma control driver. (Configure with MTweaks or EX Kernel Manager).
Lots of tracing and debug logging disabled, further reducing kernel size.
CONFIG_DISPLAY_USE_INFO
CONFIG_SEC_DISPLAYPORT_LOGGER
CONFIG_FB_MSM_MDSS_XLOG_DEBUG
CONFIG_SEC_FILE_LEAK_DEBUG
CONFIG_SEC_DEBUG_USER
CONFIG_SEC_DEBUG_SUMMARY
CONFIG_SCSI_UFSHCD_CMD_LOGGING
CONFIG_MSM_SMEM_LOGGING
CONFIG_PROFILING
CONFIG_DEBUG_INFO
CONFIG_SCHED_DEBUG
CONFIG_SEC_PM_DEBUG
CONFIG_CORESIGHT
Built as monolithic kernel (i.e. without CONFIG_MODULES).
Built as relocatable code (CONFIG_RELOCATABLE_KERNEL).
Assembler symbols stripped (CONFIG_STRIP_ASM_SYMS set).
Embedded kernel config (reported via /proc/config.gz) now falsely reports stock settings to allow disabling of superfluous kernel features that otherwise cause grave Android System warning on boot.
v0.99.9 (2018-11-13)
Rebased on ARJ3 kernel source code and boot images.
v0.99.8 (2018-11-10)
Updated to Linux 4.4.163.
More than 100 fixes applied from upstream AOSP android-4.4 and android 4.4-o branches.
Lots of tracing and debug logging disabled:
CONFIG_IPC_LOGGING (debug logging for IPC drivers)
CONFIG_QCOM_RTB (register tracing)
CONFIG_TRACER_PKT (for tracing IPC protocols)
CONFIG_FTRACE (kernel tracing infrastructure)
CONFIG_CPU_FREQ_SWITCH_PROFILER (CPU frequency switch profiler)
CONFIG_TRACING_EVENTS_GPIO (traces GPIO subsystem)
Fixes to allow kernel to build when above logging and tracing options are disabled.
v0.99.7 (2018-10-30)
Rebased on ARH5 kernel source code.
Reworked the v4l2 fix that restores liboemcrypto-dependent apps to working state.
v0.99.6 (2018-10-28)
v4l2 fixes to restore liboemcrypto-dependent apps to working state.
v0.99.5 (2018-10-21)
Updated to Linux 4.4.162.
v0.99.4 (2018-10-19)
Initial public release, based on Linux 4.4.161.
v0.99.3
Internal build, based on Linux 4.4.160.
v0.99.2
Internal build, based on Linux 4.4.159.
v0.99.1
Initial internal build, based on Linux 4.4.78.

It begins! Awesome to finally see a custom kernel for the Tab S4.

I want to test for you once I can get root back

ianmacd said:
Change log
v0.99.4 (2018-10-19)
Initial public release, based on Linux 4.4.161. Caution: This kernel remains completely untested on the T835.
v0.99.3
Internal build, based on Linux 4.4.160.
v0.99.2
Internal build, based on Linux 4.4.159.
v0.99.1
Initial internal build, based on Linux 4.4.78.
Click to expand...
Click to collapse
Flashed on T835 device doesnt even get past the Boot (custom device) screen is there a way to get logs without using a computer?
Sent from my Samsung SM-G950F using XDA Labs

dr460nf1r3 said:
Flashed on T835 device doesnt even get past the Boot (custom device) screen is there a way to get logs without using a computer?
Click to expand...
Click to collapse
I'll look into it this evening. I'm just about to get off a plane.
Were there any errors when installing? Was your device properly detected as a T835?
Sent from my SM-G965F using XDA Labs

ianmacd said:
I'll look into it this evening. I'm just about to get off a plane.
Were there any errors when installing? Was your device properly detected as a T835?
Click to expand...
Click to collapse
Installing just fine, correctly detected as well.
Sent from my Samsung SM-G950F using XDA Labs

dr460nf1r3 said:
Installing just fine, correctly detected as well.
Click to expand...
Click to collapse
I've gone through the ramdisk of the T835's boot image with a fine-tooth comb and can find nothing untoward. I also verified that I properly removed the dm-verity flag from the T835's device tree.
There are actually very few source code differences between the T830 and T835. Both can be built from a single tree. The only differences lie in the kernel config file and the device tree, but I am building with the default T835 configuration, and with the proper device tree for that device.
Let's try at least ruling out my installer code. Please image-flash this new boot image[/i] to your device and tell me if it boot-loops. If it does, my installer isn't the problem, because it's only used for a ZIP flash. I've already checked the installer code and can't see any bugs, so I don't think the issue lies there.
Can you also please tell me which version of the firmware your device is running? Possibly there's an issue there, too. Samsung has so far released the source to the ARGH kernel only. This seems to work fine on my ARH5 firmware, but it's uncertain whether it would still work on something based on ARI*, and I've seen that a couple of countries do now have ARI firmware available. Mind you, even if it wasn't compatible, it should still get as far as booting.
Anyway, please test that boot image and let me know your firmware version.

While I soldier on with the issues afflicting the T835 build, can anyone else verify the T830 build as working for them?
Don't be shy; I'm running it on my own device, so I'm certain that build boots.

ianmacd said:
While I soldier on with the issues afflicting the T835 build, can anyone else verify the T830 build as working for them?
Don't be shy; I'm running it on my own device, so I'm certain that build boots.
Click to expand...
Click to collapse
Sorry for the noob question if i flash this kernal on my SM-T835 will i lose DEX ? Sorry i'm not quite understanding what KERNEL does ? Thanks in advance!

N1NJATH3ORY said:
Sorry for the noob question if i flash this kernal on my SM-T835 will i lose DEX ? Sorry i'm not quite understanding what KERNEL does?
Click to expand...
Click to collapse
When the kernel is working as intended, you won't lose DeX, but it currently isn't even booting on the T835.
Only those who are able to assist in debugging the current boot failure should install the T835 build at this time.
The T830 build, on the other hand, is rock solid for me, and I encourage anyone who is capable of recovering from an unexpected bootloop to try it out.

Version 0.99.5 released.
This release updates the kernel to the latest upstream Linux.
T830 owners, install at will. T835 owners, beware: The previous release has been reported unbootable on this model, and this release is likely to be similarly afflicted. Investigations are ongoing. Until this issue is resolved, the whole project has been downgraded to alpha status.
Change log
Updated to Linux 4.4.162. Caution: This release is likely to cause a bootloop on the T835.

ianmacd said:
I've gone through the ramdisk of the T835's boot image with a fine-tooth comb and can find nothing untoward. I also verified that I properly removed the dm-verity flag from the T835's device tree.
There are actually very few source code differences between the T830 and T835. Both can be built from a single tree. The only differences lie in the kernel config file and the device tree, but I am building with the default T835 configuration, and with the proper device tree for that device.
Let's try at least ruling out my installer code. Please image-flash this new boot image[/i] to your device and tell me if it boot-loops. If it does, my installer isn't the problem, because it's only used for a ZIP flash. I've already checked the installer code and can't see any bugs, so I don't think the issue lies there.
Can you also please tell me which version of the firmware your device is running? Possibly there's an issue there, too. Samsung has so far released the source to the ARGH kernel only. This seems to work fine on my ARH5 firmware, but it's uncertain whether it would still work on something based on ARI*, and I've seen that a couple of countries do now have ARI firmware available. Mind you, even if it wasn't compatible, it should still get as far as booting.
Anyway, please test that boot image and let me know your firmware version.
Click to expand...
Click to collapse
Firmware Version ist arh5 and after flashing your img the device still constantly reboots on the start screen and doesnt even get to the boot Screen
Sent from my Samsung SM-G950F using XDA Labs

dr460nf1r3 said:
Firmware Version ist arh5 and after flashing your img the device still constantly reboots on the start screen and doesnt even get to the boot Screen
Click to expand...
Click to collapse
Thanks. That absolves the installer of any wrongdoing, at least.
Something is fundamentally wrong with the kernel for the T835.
The boot image is taken from stock firmware, and modified just enough to allow a custom kernel to boot. I very much doubt the problem lies there. A virtually identical image works for the T830.
The kernel config used is the one supplied by Samsung. The only modifications made to it are the same ones I made to the T830's.
I think my next step will be to produce a kernel built without downstreaming the 4.4.y Linux branch, so back to 4.4.78. If that works, it will indicate that an error affecting only the T835 was introduced during all of my merging of the upstream kernel.
I'll post again when I've built the kernel, which won't be for a few hours, as I'm on holiday at the moment.
Sent from my SM-G965F using XDA Labs

ianmacd said:
I think my next step will be to produce a kernel built without downstreaming the 4.4.y Linux branch, so back to 4.4.78. If that works, it will indicate that an error affecting only the T835 was introduced during all of my merging of the upstream kernel.
Click to expand...
Click to collapse
OK, @dr460nf1r3, please try this new T835 build.
This is rewound to 4.4.78, with just a few extra cherry-picked commits to enable it to build cleanly and boot without triggering dm-verity.
In other words, this kernel should be 99% identical to the one that shipped with the machine. This assumes that the source as supplied by Samsung was actually used to build the stock kernel.. They have been known to publish sources that don't match what's on the machine.

ianmacd said:
OK, @dr460nf1r3, please try this new T835 build.
This is rewound to 4.4.78, with just a few extra cherry-picked commits to enable it to build cleanly and boot without triggering dm-verity.
In other words, this kernel should be 99% identical to the one that shipped with the machine. This assumes that the source as supplied by Samsung was actually used to build the stock kernel.. They have been known to publish sources that don't match what's on the machine.
Click to expand...
Click to collapse
Thanks, flashing now will report back in a few minutes
Sent from my Samsung SM-G950F using XDA Labs
---------- Post added at 05:44 PM ---------- Previous post was at 05:17 PM ----------
ianmacd said:
OK, @dr460nf1r3, please try this new T835 build.
This is rewound to 4.4.78, with just a few extra cherry-picked commits to enable it to build cleanly and boot without triggering dm-verity.
In other words, this kernel should be 99% identical to the one that shipped with the machine. This assumes that the source as supplied by Samsung was actually used to build the stock kernel.. They have been known to publish sources that don't match what's on the machine.
Click to expand...
Click to collapse
Did not work still the same issue.. flashed via twrp to boot partition. Noob question, the boot backup i got is 64mb while your kernel hardly has 25.. whats going on here?
Sent from my Samsung SM-G950F using XDA Labs

dr460nf1r3 said:
Did not work still the same issue.. flashed via twrp to boot partition.
Click to expand...
Click to collapse
Well, that's disappointing. I was hoping that it was my screw-up, rather than Samsung's, but at this point almost everything I've done has been backed out and it still won't boot.
Noob question, the boot backup i got is 64mb while your kernel hardly has 25.. whats going on here?
Click to expand...
Click to collapse
Good question.
Your back-up is of the entire partition, including the area with no data on it, so you're getting a file the same size as the partition itself. My boot image contains just the data segment, so it's smaller.
If you pull the stock boot image from the AP file of Samsung's firmware, you'll see that it's a very similar size to mine (slightly smaller, actually):
Code:
$ unzip -p T835XXU1ARH5_T835OXM1ARH5_PHN.zip AP_T835XXU1ARH5_CL14008523_QB19263559_REV00_user_low_ship_MULTI_CERT_meta.tar.md5| tar xf - -O boot.img.\*lz4 | lz4 -dc > boot.img
$ ls -l boot.img
-rw-rw-r--. 1 ianmacd ianmacd 23593232 Oct 21 22:01 boot.img
$ file boot.img
boot.img: Android bootimg, kernel (0x8000), ramdisk (0x2000000), page size: 4096, cmdline (console=null androidboot.hardware=qcom user_debug=31 msm_rtb.filter=0x37 ehci-hcd.park=3 lpm_le)
So, what now?
I'll see which other minor changes I can back out, in an effort to arrive at a kernel built from source that is as close to stock as possible. If you're wondering Why doesn't he just build from pristine sources?, the answer is: Because Samsung's source code won't even build out of the box. Many of the kernel header files are simply not in the expected locations. Alas, this is a fairly common problem with Samsung's kernel source code releases.
I suspect the solution to this problem may actually lie in changes that have yet to be made, rather than changes made that need to be reverted. In other words, the T835 may require some kernel modifications or configuration that the T830 doesn't. Theoretically, a kernel compiled from Samsung's pristine sources should just work, but that's starting to look unlikely now.
I'm hoping that I can enable/disable a few further options in the kernel config, rebuild and produce a kernel that works for you. If, however, the problem is that the source itself is faulty, we may have to wait for a future release by Samsung to give us something that compiles into a working kernel.
But I don't intend to throw in the towel on the T835 just yet. There are still a few more things we can try.

ianmacd said:
Well, that's disappointing. I was hoping that it was my screw-up, rather than Samsung's, but at this point almost everything I've done has been backed out and it still won't boot.
Good question.
Your back-up is of the entire partition, including the area with no data on it, so you're getting a file the same size as the partition itself. My boot image contains just the data segment, so it's smaller.
If you pull the stock boot image from the AP file of Samsung's firmware, you'll see that it's a very similar size to mine (slightly smaller, actually):
So, what now?
I'll see which other minor changes I can back out, in an effort to arrive at a kernel built from source that is as close to stock as possible. If you're wondering Why doesn't he just build from pristine sources?, the answer is: Because Samsung's source code won't even build out of the box. Many of the kernel header files are simply not in the expected locations. Alas, this is a fairly common problem with Samsung's kernel source code releases.
I suspect the solution to this problem may actually lie in changes that have yet to be made, rather than changes made that need to be reverted. In other words, the T835 may require some kernel modifications or configuration that the T830 doesn't. Theoretically, a kernel compiled from Samsung's pristine sources should just work, but that's starting to look unlikely now.
I'm hoping that I can enable/disable a few further options in the kernel config, rebuild and produce a kernel that works for you. If, however, the problem is that the source itself is faulty, we may have to wait for a future release by Samsung to give us something that compiles into a working kernel.
But I don't intend to throw in the towel on the T835 just yet. There are still a few more things we can try.
Click to expand...
Click to collapse
Thanks for explaining everything for me. Id like to help you were i can but i dont have a computer by my hands right now for the next time
Sent from my gts4llte using XDA Labs

dr460nf1r3 said:
Thanks for explaining everything for me. Id like to help you were i can but i dont have a computer by my hands right now for the next time
Click to expand...
Click to collapse
Here's a new build to try. This one reverts the last few changes I originally made to the T835's kernel configuration before building. This is as close to stock as possible, whilst still being able to build.
If this doesn't boot, it pretty much means that Samsung has supplied code for the T835 that simply will not compile into a working kernel. At that point, we'll probably have to wait for updated sources. I already have a request pending with Samsung for the release of the BRI sources.
Just to be clear, the current status quo as I understand it is that the Samsung logo never starts to be written from left to right. You never get past the static screen with the device name and the word Custom. Is that correct?

ianmacd said:
Here's a new build to try. This one reverts the last few changes I originally made to the T835's kernel configuration before building. This is as close to stock as possible, whilst still being able to build.
If this doesn't boot, it pretty much means that Samsung has supplied code for the T835 that simply will not compile into a working kernel. At that point, we'll probably have to wait for updated sources. I already have a request pending with Samsung for the release of the BRI sources.
Just to be clear, the current status quo as I understand it is that the Samsung logo never starts to be written from left to right. You never get past the static screen with the device name and the word Custom. Is that correct?
Click to expand...
Click to collapse
Im sorry to tell you but this doesnt boot either in fact it doesnt even reboot the static screen. Your right about the current status quo sadly.
Sent from my Samsung SM-G950F using XDA Labs

[REFERENCE] Umbrella Kernel

WARNING:
This is not a post targeted to end users. It is a development reference. If you expect any installable download or even added features out of this thread, please close your browser. Thank you.
What is Umbrella?
Umbrella is a project that aims to make the kernel sources that HMD released for Nokia 8 Sirocco (A1N) compatible with the Nokia 8 (NB1). The idea behind this is to replace the outdated 8.0 kernel sources that HMD released for NB1 with more up to date ones that are used in the 9.0 builds for Nokia 8 Sirocco.
Why do this, you might ask. Well, the answer is simple: The devices are so similar that HMD / FIH already have their kernel sources in a shared source tree. You can validate that yourself, by downloading the kernel config from a stock NB1 kernel (under /proc/config.gz), unpacking it, and searching for the commended entry "CONFIG_FIH_A1N". What umbrella does is take the sources that were released for A1N, readd all device specific files for NB1 (they were pruned) from it's original kernel soure, and integrate the stock kernel config (also called defconf) from NB1.
Doing this also lead to some other small quality of life improvements that are not directly relevant to an end user.
Umbrella contains the latest changes from linux-stable (v4.4.179 at the time of writing, compared to the stock v4.4.153), and Qualcomms Codeaurora upstream
The WiFi driver from Qualcomm is compiled directly into the kernel, instead of being loaded as a module. This allows you to flash umbrella based kernels to every build version while keeping everything else working correctly. The stock kernels use signature enforcement, which means that the wifi module that is loaded from the system partition has to be signed against the kernel, which is not the case for every custom kernel or even the kernels that were built for a different security patch.
Unlike the officially released kernel sources, umbrella does not have stupid typos in it's device trees that cause the phone to display white bars on all of your screen etc.
Umbrella disables the block that FIH put in place to prevent users from rebooting into EDL mode from within android (using adb reboot edl).
Umbrella also includes a patch that causes the device to not reset it's entire memory when the kernel crashes, therefore retaining the last kernel output log, which can be used for debugging
You can compile the kernel with compilers newer than GCC 4.9 (not clang though), without having it immideately crash at boot.
It includes a tool that automatically sets up a crosscompiling environment for the kernel.
What Umbrella is not
Umbrella is not a project to add significant new features, or the ability to tweak things beyond what the stock kernel already offers (which is technically not that bad). It aims to be a reference kernel, a base for (potentially) other kernels that are based on it and add those features. I know that that is kind of a broad goal, considering I am the only one who seems to do actual development for this phone, but who knows. Having a lower entry level might help in case someone is curious and wants to get into kernel hacking. And I would certainly be happy if I wasn't the only one developing for this device.
If you want Umbrella to contain features like:
Overclocking
More governors / schedulers / whatever
Color / Sound / whatever control
Wakelock blocking
etc. etc. etc.
then please Alt-F4 your browser right now. Ok, don't do that but at least please don't request it because it will make you get ignored, nothing else.
Why the name Umbrella?
While I developed the initial prototype I watched through 3 Resident Evil movies, and this is kinda a zombie project, so I think the name fits quite well.
Why are you posting this?
I am posting this because I am hoping that it will be useful for anyone that would like to get into kernel development and tweaking without the hassle that comes with setting up the kernel sources that are released by HMD.
But, one disclaimer: I am not a kernel developer. I am a curious CS student suffering from a bad mix of too much time and stupid ideas that solve stupid problems. I am trying my best to produce something useful and be of help, but please don't expect wonders from me, thanks.
Links?
Source: https://github.com/resident-nokia/umbrella
Download: None, this is a development reference.

Looks promising
Sent from my NB1 using XDA Labs

Nice. this will likely be useful in the future

Updated the umbrella source to the latest 4.4.180 kernel, and May 07 CAF tag (LA.UM.7.4.r1-05100-8x98.0). Also readded some NB1 specific code where it was missing (discovered by doing a diff against the 5140 kernel source that Nokia recently released).
Just in case anyone actually cares about it

THMSP said:
Updated the umbrella source to the latest 4.4.180 kernel, and May 07 CAF tag (LA.UM.7.4.r1-05100-8x98.0). Also readded some NB1 specific code where it was missing (discovered by doing a diff against the 5140 kernel source that Nokia recently released).
Just in case anyone actually cares about it
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Click to collapse
I do. Who knows, in a year's time I might have enough knowledge to build a custom Rom for this phone

Kernel sources which is used on pie has been released officially. Finally, we have an "original" kernel and we've got closed one more step to custom roms.
https://www.nokia.com/phones/en_int/opensource/

techno_man000 said:
Kernel sources which is used on pie has been released officially. Finally, we have an "original" kernel and we've got closed one more step to custom roms.
https://www.nokia.com/phones/en_int/opensource/
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@THMSP it would be interesting to let us know how different is your kernel mod from the newly released official pie kernel for Nokia 8

MDV106 said:
@THMSP it would be interesting to let us know how different is your kernel mod from the newly released official pie kernel for Nokia 8
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As I described here: https://forum.xda-developers.com/nokia-8/development/official-source-code-releases-nokia-8-t3930324, they are identical. The only difference are the device tree files (which still contain typos that break the display), and of course all modifications I made to the sirocco kernel source that Umbrella is based on (wifi driver, EDL mode reactivation, upstreaming, etc.)

THMSP said:
As I described here: https://forum.xda-developers.com/nokia-8/development/official-source-code-releases-nokia-8-t3930324, they are identical. The only difference are the device tree files (which still contain typos that break the display), and of course all modifications I made to the sirocco kernel source that Umbrella is based on (wifi driver, EDL mode reactivation, upstreaming, etc.)
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So, are these new codes broken like 4.84?

techno_man000 said:
So, are these new codes broken like 4.84?
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I wouldn't call Nokia sources broken, but I would call them incomplete, outdated and impractical to work with. And that hasn't changed.

Iam currently building device tree for nokia 8..
Unable to figure out how to edit init folder specifically for nokia8

[email protected] said:
Iam currently building device tree for nokia 8..
Unable to figure out how to edit init folder specifically for nokia8
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Please do so! We can't let this phone die so early!

which defconfig file should choose?

lk

[email protected] said:
which defconfig file should choose?
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nb1_defconfig is for Nokia 8

Can somebody help me? I have built Lineage OS 16.0 for the Nokia 8 with the Umbrella Kernel. However I am facing issues with getting it into work. Firstly TWRP fails to flash it with error 7. I am including the recovery.log file in case anyone wants more detail. I then proceeded to extract the payload.bin file, and flashed boot.img and system.img seperately. However that didnt work either as my phone got stuck at the Bootloader unlocked warning screen. If anyone is interesteed I can upload the .zip outputed by the build
Device Tree: https://github.com/GPUCode/android_device_nokia_nb1
Recovery.log: https://hastebin.com/akohutiwed.sql
Thanks in advanced

emufan4568 said:
Can somebody help me? I have built Lineage OS 16.0 for the Nokia 8 with the Umbrella Kernel. However I am facing issues with getting it into work. Firstly TWRP fails to flash it with error 7. I am including the recovery.log file in case anyone wants more detail. I then proceeded to extract the payload.bin file, and flashed boot.img and system.img seperately. However that didnt work either as my phone got stuck at the Bootloader unlocked warning screen. If anyone is interesteed I can upload the .zip outputed by the build
Device Tree: https://github.com/GPUCode/android_device_nokia_nb1
Recovery.log: https://hastebin.com/akohutiwed.sql
Thanks in advanced
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hey, did you wipe userdata before flashing this? I think you need to do that, like when switching to using GSIs.
also, have you checked this https://github.com/resident-nokia/twrp? Specifically the fstab file for NB1.

oaid said:
hey, did you wipe userdata before flashing this? I think you need to do that, like when switching to using GSIs.
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Thanks for the suggestion. I have flashed GSIs before but never had any problems. Also I cannot find any userdata partition in TWRP. I asked in the Lineage OS discord and I was told that probably that TWRP image is broken. I am confused

emufan4568 said:
Thanks for the suggestion. I have flashed GSIs before but never had any problems. Also I cannot find any userdata partition in TWRP. I asked in the Lineage OS discord and I was told that probably that TWRP image is broken. I am confused
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that's the data partition, if I'm not mistaken ?*
which twrp image are you using? Maybe try Dorian's latest?

oaid said:
that's the data partition, if I'm not mistaken ?*
which twrp image are you using? Maybe try Dorian's latest?
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Yes I am using the latest TWRP. Before flashing I erased the data partition but still the error persisted