Hi all,
Looking to build my first custom Rom and had some queries terminology-wise.
What is the relationship between the kernel and Google's android platform? For instance, is froyo tied to a specific kernel and is this in the source tree?
Second q: HTC release their kernel sources. Say I wanted to get a froyo build up for a device that currently only has eclair, would the procedure be to diff the HTC modifications against the vanilla version and then make the appropriate changes to froyo?
Third q: what makes a Rom specific to a device? Probably linked to first question...
Many thanks,
Martin
Sent from my HTC Wildfire using XDA App
The kernel is basically just a linux kernel with device specific drivers and such added. I've done a 'diff' between the Eris 2.6.29 kernel from HTC and the 'generic' 2.6.29 kernel from kernel.org. It's kind of neat to see the difference. I highly recommend you do that.
There are also device specific drivers in the file structure that the ROM needs in order to function.
What I've done is compile AOSP from source, compile the kernel from source, zip up the needed files/folders, signed the ROM, and then flashed it to test. If you look at Android Builder in my sig, you can figure out the difference between the Eris and your device. You'll have to change the kernel that gets downloaded, of course. And it really just gives you a basic ROM without the device specific drivers, so things will not work without figuring the rest out. Grab a stock ROM to get drivers, libs, etc. out of.
/system/usr/keychars & /system/usr/keylayout usually have the keyboard drivers, which are somewhat important.
Also in my sig is the SgtShultz ROM where I tried to make a usable ROM from as close to source as possible. You might get some ideas from there. I still haven't figured out how to get the audio to work. If I get that worked out, I'll actually start using the ROM daily and work out the rest!
Froyo seems to work with kernel versions 2.6.29+, btw.
Many thanks for this; it's given me a good set of places to start reading.
Just pulling down all the AOSP source as we speak, with the hopes of getting a basic build up in the near future
gnarlyc said:
What I've done is compile AOSP from source, compile the kernel from source, zip up the needed files/folders, signed the ROM, and then flashed it to test. If you look at Android Builder in my sig, you can figure out the difference between the Eris and your device. You'll have to change the kernel that gets downloaded, of course. And it really just gives you a basic ROM without the device specific drivers, so things will not work without figuring the rest out. Grab a stock ROM to get drivers, libs, etc. out of.
[...]
/system/usr/keychars & /system/usr/keylayout usually have the keyboard drivers, which are somewhat important.
[...]
Froyo seems to work with kernel versions 2.6.29+, btw.
Click to expand...
Click to collapse
A couple of questions on this front...
I can see, obviously, where to get the kernel source and needed drivers; I am, however, unclear as to where I should obtain AOSP drivers from (to go, for instance, in /devices/htc/buzz and/devices/htc/buzz-common). Can I extract these from my device? (or do I need to wait until they release Froyo and then extract them from a device running the newer build?) Where on the device should I be looking for this driver set?
Thanks again,
Martin
MartinEve said:
A couple of questions on this front...
I can see, obviously, where to get the kernel source and needed drivers; I am, however, unclear as to where I should obtain AOSP drivers from (to go, for instance, in /devices/htc/buzz and/devices/htc/buzz-common). Can I extract these from my device? (or do I need to wait until they release Froyo and then extract them from a device running the newer build?) Where on the device should I be looking for this driver set?
Thanks again,
Martin
Click to expand...
Click to collapse
For the most part, any Eclair drivers seem to work. At least that's what I have used for the Eris. 2.1 -> 2.2 isn't too big of a jump. I used drivers from a stock 2.1 ROM.
Look up vendor tree, vendor config, and 'extract-files.sh'. You'll see what people with other devices have done. I have yet to quite get the whole vendor tree thing worked out, but others have. You can just come up with a list of needed drivers to add to the 'extract-files.sh' script and just copy those files in manually. (That's what I have done.) This will get pretty close to making an AOSP build complete. However, it appears that actually using the vendor tree setup while compiling will get things 'right'. There appear to be some libs that will compile differently for different devices.
So, basically, if you compile AOSP without a vendor tree for your device, the build will be located in out/target/product/generic. (And, you can copy drivers in later while using the kitchen, but you might miss out on some AOSP stuff with device-specific changes.) If you use the vendor tree, it will be in /out/target/product/buzz and will contain the drivers that the 'extract-files.sh' script grabbed from your device along with custom compiled libs.
If you are able to get a working vendor tree for your device, it will be helpful to the entire community. They'll all be able to use it for their builds. I highly recommend doing that. Most groups use github or something similar to post the code.
I still have much to learn myself, and you are starting to reach my limit! Good stuff.
Hi,
Many thanks for your reply; to a degree, it's about knowing the terms to search for -- the extract-files.sh is a godsend for information that I would have otherwise missed.
Anyway, onwards to build a usable vendor tree
Best,
Martin
Related
Hello, I'm new to all this Android stuff (I don't even have a phone yet, but its on it way)
I have been reading up on custom ROM creation but there are some things I don't quite understand.
Let's say I have a phone in Android 2.3. I want to create an Android 4.0 ROM to put on the phone.
Now... to compile Android 4.0 I need the drivers for my phone (which I doubt I will ever have access too since its only a cheap Android with a MediaTek CPU)
So I have a 2.3 ROM that contains all the compiled drivers and the Android 4.0 source code.
Is it possible to compile 4.0 and replace the zImage (if I'm correct) with the 2.3 zImage. From what I have read, that's where all the drivers are stored.
I guess its not that simple since I also think the zImage contains the OS. If so, is it then possible to extract the zImage and replace the invalid driver files in 4.0 with the correct drivers from 2.3?
Also, I think my phone will arrive with an annoying UI, is it possible to just get any 2.3 ROM (that doesn't have an annoying UI and shares the same CPU as my phone) and replace the zImage in that with my phones 2.3 zImage?
Sorry, if my questions are stupid but this is all new to me. I've tryed to read up on this but nothing is straight to the point.
Thanks
Anyone there?
try out some roms first. see what you like and dont like. it'll probably give you a better idea for how you would make your own rom.
I don't think you could just port an entire zimage to ICs and say it will work (it might not even compile i think). It won't work. You could probably take some drivers' code (screen, speaker, etc), modify them a bit so it compiles, and test to so if it works. You more than likely have to modify the ICS code also so it works. And the zimage is just the kernel no? And the kernel really only has to do with low level system processes, drivers, etc. I think UI's and such are more fitted in frameworks and such.
Personally if it was so easy to port ICS by simply replacing the zimage or file with another, ICS would have been ported to many devices, fully working, by now.
Kailkti said:
I don't think you could just port an entire zimage to ICs and say it will work (it might not even compile i think). It won't work. You could probably take some drivers' code (screen, speaker, etc), modify them a bit so it compiles, and test to so if it works. You more than likely have to modify the ICS code also so it works. And the zimage is just the kernel no? And the kernel really only has to do with low level system processes, drivers, etc. I think UI's and such are more fitted in frameworks and such.
Personally if it was so easy to port ICS by simply replacing the zimage or file with another, ICS would have been ported to many devices, fully working, by now.
Click to expand...
Click to collapse
Yeh, but my problem is I don't have the drivers for the phone. I just have the stock ROM that come with it.
Is not that simple. I am 99% sure that you can't do that.
The phone I'm getting has a horrible theme on it. Its running Android 2.3
I have the ROM for a very similar phone (also using Android 2.3), uses the exact same CPU so it should be compiled using the correct platform.
Is it possible to use that phones ROM but replace it with my phones Kernel and .prop (so it has all my phones drivers and settings etc...)?
the hard work required in making a custom rom
I think you can take from the stock rom and compared with existing custom rom
but some sources are not shared freely as an example Tegra
CMIIW
I will mess about with the ROM when I get my phone. Hopefully I wont brick it...
I too am fairly new to android. I spent a couple weeks reading and watching TONS of youtube videos on how to ROOT and Unlock my bootloader. My best advice from one n00b to another would be to do the same. In particular...research how to do it on YOUR phone. Also, Roms are device specific. I recommend you finding the forum here on XDA for your phone and read up on whatever ROMS are available here. This might not be the ONLY place to find ROMS, but this place simply rocks! Once you get your device rooted and if necessary, your bootloader unlocked...you can easily try out any ROM without much fear. Just make a good backup...make sure you also have a factory recovery image too...just in case. For backups...if you install and use Clockwork Mod (CWM) you can use the nandroid backup it offers. I bought Titanium backup from the market and used it to do a full backup before I started...it backs up to dropbox even, which was a nice feature for me. Extra safety so incase I hosed my external SD card which had my backups...I could easily retrieve a backup ANY place that had internet access. Lastly...get ready to have some FUN! Flashing ROMs is VERY addictive!! :-D
Ok, Thanks. I will see what I can do then.
Hi I looked for sometime for answers but could not find anything relevant.
Looking to get the ftdi VCP drivers to install on Xoom. Which means I either have to compile a kernel or add them as a module. I can not for the life of me find the correct source tree.
I downloaded kernel 2.6.36.3 from google which matches my kernel version.
My kernel version on the tablet is 2.6.36.3-gb899258 .
When I cross compile the module and try to do an insmod its complaining about the magic version is different which leads me to believe that I have the wrong kernel.
Where can I get the right stock kernel?
If i can not find it there is another option to download the config.gz from the device and recompile another version of the kernel with native support for the ftdi drivers.. How do i just install just the kernel on the device? Is it a uImage bzImage and how do I just flash that?
cd
Thanks
edit:
scrap that ...
sorry, not really helpful in your case
I'm assuming you got your source from here? This is the link from the Android website:
git clone https://android.googlesource.com/kernel/tegra.git
If you decide to go the route of compiling another kernel source, the easiest way (and a good way to keep snapshots of various configs) would be to use Koush's AnyKernel to flash the kernel. I don't know anything about what you're trying to do but I hope that helps some.
Yep the code comes from there.....
I finally got it to work , I downloaded the stock kernel from google then when I make the modules I had to modify the Makefile to get it to match the kernel versions.
It seems to work for now...
Thanks for your help
I realize people gave up slightly on the whole kexec thing over radio worries, but I now have the module compiling and inserting without error into the Droid2/DroidX gingerbread kernel. Next comes cross compiling the kexec-tools for userspace, to allow us to attempt inserting a different kernel.
To build, you'll need a compiled DroidX kernel from source, as well as the android NDK.
To build, make sure you have downloaded the DroidX GB kernel source and compiled it. There are guides everywhere on how to build Android kernels. Just make sure you use the proper cross compiler.
http://sourceforge.n....l.tgz/download
When you build, make sure to use
Code:
make mapphone_defconfig
Once the kernel is built, clone my repo and edit envsetup.sh to reflect the correct paths to your kernel source directory and the android NDK.
https://github.com/i...kexec-mod-d2-dx
Then, source it:
Code:
source envsetup.sh
Then, just run
Code:
make
and cross your fingers. You should then have a fresh kexec_load.ko file!
To see if it loads, you'll need to copy it to your sdcard, and then on the phone, using a console, do the following:
Code:
su (click allow)
insmod /sdcard/path/to/kexec_load.ko
If you don't get any errors, it inserted! Now, of course, to actually use it, we'd need the kexec-tools built, which I haven't gotten ready yet...but they're coming! To remove the module (no reason to leave it in memory for now):
Code:
rmmod kexec_load
Happy hacking, and help is always appreciated!
This looks great! If you need any help just ask
Thanks! I probably could actually use some. I'm looking at eternity project's git repos now, and am trying to figure out how they managed to get atags working, with the whole procfs thing...still scratching my head there.
I'm looking at eternity project's git repos now, and am trying to figure out how they managed to get atags working, with the whole procfs thing...still scratching my head there, though I do have an atags module working, except it doesn't do anything without atags in the procfs (http://lists.infradead.org/pipermail/kexec/2011-January/004795.html).
kexec-tools:
https://github.com/i...xec-tools-dx-d2
To build, see the README.
Then, copy the binaries from /build/sbin/* to your device, and the move them to the /system/bin directory, and chmod them 770 to make them executable.
mod-atags:
https://github.com/i...mod-atags-d2-dx
Now, if I/we can just get atags and procfs stuff taken care of, we'll be able to go to the next step. I already have atags compiling as a module, but it won't stay inserted because we have no atags in the procfs. Note I can't just trace through code like this and know what everything is doing, but I know enough to hack at it and be dangerous
I know this is kind of off topic, but would this help us people with Motorola Atrix 2? Does it use the same radio?
calebcoverdale said:
I know this is kind of off topic, but would this help us people with Motorola Atrix 2? Does it use the same radio?
Click to expand...
Click to collapse
No idea. I haven't even gotten the kernel to change yet, so I haven't gotten to mess with radio yet. The method itself should/would work though, but radio will require reverse engineering...perhaps find a similar phone with an open bootloader and disassemble and attempt to clone it's modules.
The latest change I made may or may not work, it was an attempt to remove atags from the kexec module based on an old patch I found, which added the functionality. This at leaset made kexec -l zImage work, but when I run kexec -e, the kexec binary complains about atags not being there...hrmmmph.
I may have to revert it (and will if we can get atags somehow) ...but if we can get the kexec bin to ignore /proc/atags or just find a way to rip them out of the running kernel, we'll be in business.
The commit: https://github.com/ilikenwf/kexec-mod-d2-dx/commit/12dffe0ea286be0fe9ab0303a5a35ed92be4ee2c
I'm also looking into 2ndboot.
I like where this is going! Keep working!
Sent from my DROID2 using xda premium
Okies, so, I emailed aliasxerog (original kexec-mod writer), and I hope he'll get back to me. Even though his twitter says he's a "former android developer," maybe he'll be willing to give me some hints so I can pick up where he left off.
I also got the froyo version of the module building properly based on his module, yet again, (all after SBF'ing my phone back down to motoblur froyo - yech!) but neither currently work... (note there's a gingerbread and a froyo branch on my repo): https://github.com/i...kexec-mod-d2-dx
The froyo one throws the following error, which stops me dead in the water:
Code:
Could not find a free area of memory of 3007dc bytes...
The gingerbread one loads the kernel into memory but won't execute it due to our not having atags.
We've moved our git repos to an organization for easier collaboration:
https://github.com/organizations/D2-DX-Customboot
links are imcomplete.
use URL lable pls.
Cross compiler version ?
hello,
Sorry but I am not able to use the sourceforge link that you provided to download kernel source .. Also please share what cross compiler version is to be used....
Thanks in advance.
Since development for the Sidekick 4G has stopped I decided to try and port the CM11 M10 snapshot from the Galaxy S 4G using this guide. I used the Galaxy S 4G as port ROM since most of the specs are the same as the SK4G. The base ROM I used is ayoteddy"s KJ2 Deodexed & rooted ROM. I followed the guide and flashed the ROM I made but the phone didn't boot. It stays stuck at the tmobile startup screen and then bootloops. I took a logcat and see a lot of errors but idk how to correct them. I tried uploading the ROMs I used and the one I created but it only let me upload the logcat.
Hey,
Its awesome to see some more effort in this phone but when porting a ROM one of the main prerequisites is the base being the same android version.
So to port cm11 over you would need a kitkat kernel and ROM for the sk4g already.
What would be real helpful is to get the gingerbread kernel fully functional then any GB ROM could be ported fairly easily.
Or start with a kitkat kernel but both require a bit of work. If you want to take it on a can link a bunch of guides that may help
Thanks for that info. I don't have experience coding but I would like to be able to learn how to cook and port roms so I would really appreciate some guides. As I understand it, since there is no KitKat ROM available for the sk4g I would first need to make my own KitKat kernel and ROM before I would be able to port cm11? And how long do you think it would take to learn everything needed to be able to port and cook roms?
Hey,
On mobile right now so can't post a bunch of links but xda is filled with them
The best place to start would be http://www.xda-university.com
And be sure to check out the forum links as well!
For a quick set of links see the seventh post in this thread
http://forum.xda-developers.com/showthread.php?t=2348266
For a different device but those are all great places to start learning to develop for android
Keep me posted on your progress!
Took me a while to find some useful guides since I was searching with the term "port" and not "build/compile from source" since that is essentially what I'm doing. I used wiki.cyanogenmod.org/w/Doc:_porting_intro and wiki.cyanogenmod.org/w/Build_for_galaxysmtd (can't post links yet). I forked the galaxys4g repo and modified the files to be suited for the sidekick4g. Now I'm onto the building step, a couple of things already broke and I managed to fix them, but I ran into this error and haven't been able to fix it.
brunch sidekick4"ebtables is disabled on this build"
find: `src': No such file or directory
build/core/base_rules.mk:134: *** system/extras/ext4_utils: MODULE.TARGET.EXECUTABLES.setup_fs already defined by device/samsung/sidekick4g. Stop.
I researched the MODULE.TARGET.EXECUTABLES.setup_fs already defined by device/samsung/sidekick4g issue and suggestions were to delete the setup_fs file within device/samsung/sidekick4g folder. However the setup_fs file wasn't in there, I did find a setup_fs.c file and deleted that one. Then I proceeded to try the build again and ran into the same error. Another suggestion was to use grep -R setup_fs *. This command pointed to these files,
Android.mk:LOCAL_SRC_FILES := setup_fs.c
Android.mk:LOCAL_MODULE := setup_fs
Android.mk~:LOCAL_SRC_FILES := setup_fs.c
Android.mk~:LOCAL_MODULE := setup_fs
initramfs/init.herring.rc:service setup_fs /system/bin/setup_fs /dev/block/platform/s3c-sdhci.0/by-name/userdata
sidekick4g.mk: setup_fs
But I don't know what exactly I'm supposed to delete. The device repo is located at github.com/SK4G/android_device_samsung_sidekick4g.git It is a pre-build attempt version before I made suggested changes to the local repo. I tried "git push origin master", the command went through and said everything is up to date but the remote repo still wasn't changed so I haven't been able to update it.
What are you using for the device tree? The relay is a completely different device and none of the drivers would work, did you at least pull blobs and proprietary files from a sk4g?
There is a ton of setup to be done in order to build from source, you can use the cm11 source but need to make a specific device tree for the sidekick to get a working build, not to mention a ton of kernel work will be needed
For the device tree I forked the galaxys4g repo (not the galaxy s relay 4g) and then modified the files to build the sidekick4g specific device tree. When pulling the blobs and proprietary files the guide said " Your device should already be running a build of CyanogenMod for the branch you wish to build for the extract-files.sh script to function properly". Not sure if that's relevant to the errors but I was still able to pull the blobs towards the correct ~/android/system/vendor/samsung directory. As far as the kernel I downloaded the stock kernel from the samsung source website and then put it in the kernel/samsung/sidekick4g directory. The guide said that the kernel and kernel modules would be built automatically as long as I made appropritate changes to the BoardConfig.mk and I did so. I have done every step in the guide and now I'm into building but I can't get past the previously mentioned error. Should I delete the whole part of the files mentioned by the grep -R setup_fs * command or just the red part or is there another solution?
Well the blobs that were pulled and the kernel that was used was for froyo, that won't work for kitkat without a weeks worth of modification
Also the s4 is even more different than the relay and would be much harder to use anything from there
What you need at this point is to create your own device tree on github and add this to your local manifest, then the hard part is to adapt the sk4g kernel into something that will work with kitkat, once this steps are complete you can build and then fix the errors that come up, fixing any errors at this point won't help much as the files used are incompatible from the start
I should have been more specific, I used the T-Mobile Galaxy S 4G which is one the first galaxy phones. It has the same hummingbird chipset, architecture, ram/rom size, resolution, and both originally ran froyo. The guide states that the cm buildbots build a compatible kernel for me. I didn't just fork the galaxys4g repo and leave it as is. I went through the files and substituted anything that was galaxys4g device specific to fit the sidekick4g.
No problem, should have read more clearly, yes the galaxy s is very similar minus the keyboard but you can look at the work that was done to get a GB ROM booting here
http://forum.xda-developers.com/showthread.php?t=2323617
This was done on the exhibit, another very similar phone,
Even after the kernel was adapted the keyboard never worked, you check the link to his github to see what was put into it to work
The kernel built by the bot won't adapt it to work between different versions of android so you need to build this manually first then you can use it, but even then there will be a lot to do in order to get the keyboard working
Now I'm beginning to understand what you have been trying to tell me. It was hard to grasp at fist because I never really looked into building a kernel since I usually just use the stock kernel or the cm built in kernel on my devices. Now I shall redirect my efforts into building a kernel
Hi I just wanted to know if you're still building port for the sidekick 4G I still have mine and I would like to use if you have kitkat to work. I miss my sidekick 4G
Sent from my Nexus 6 using XDA Free mobile app
So I've decided to give building Android a go, considering we've recently obtained the source code for the device in question (R1 HD) and no one else has done this yet for this device. I've been following this guide, since all the other guides I've found assume there is already a GitHub repo for your device. There's literally NOTHING out there regarding this device, aside from the kernel source we've obtained in the form of a .zip archive.
I've done everything up to and including pulling the 7.0.0 r1 source with the reop sync command, and I am now stuck on the Preparing to Build section. The first thing it talks about at this point is implementing proprietary binaries into my source. I have no idea where to find proprietary binaries for my R1 HD, let alone if they even exist out there to be implemented. Literally all I have regarding this device is the kernel source in a zip file. I can't find anything else out there nor do I really know what to look for.
Can anyone tell me what to do here? I've never compiled Android or even a kernel before, and I'd really like to get something out there for this device that others can base their work off of.