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Ways to make a rom

By any chance could someone tell me the best way to make a rom, I have a droid 3 and really want to make a rom but I don't know where to start, thanks in advance
Sent from my DROID3 using XDA App

The best roms start with 3 eggs and little bit of milk to make them fluffy. Whisk briskly!
If you want to jump in, this is a good place to start http://source.android.com/source/index.html
If you just want to dip your toe in the water, then you could start with modding roms, such as adding/removing apks, theming, writing update scripts.
Find a rom and unzip it. Look inside, poke around. Don't be shy-take things apart. Peel back the layers until you find xml and png files. Then, put it all back together and see if you can get it to flash.

Thanks
Sent from my DROID3 using XDA App

thanks so much for the info!

If you download a rom and unzip it, there will be a META-INF folder- look in here- there will be some crypto certs and a com/google/android/ folder which will have the updater-script and update-binary. The script is how the phone knows what to do with the rom. Read through the script and try to decipher what it is actually doing. It will be different for some roms. For example, the cyanogen roms will back up some system apps and replace them after flashing.
You might also come across a boot.img in the root directory of the rom. If you do, there will be some instructions in the updater-script for what to do with it.
Next look in the system/app directory- you'll find a bunch of apk files. These are actually in zip format, so you could unzip them to see what is inside.
A basic test would be to add or remove an apk to the system apps and then get it to flash. Of course you'll need a rooted phone and maybe jarsigner or signapk. Signing a rom will put all those CERT.RSA files back into the META-INF/ folder, which contain crypto hashes of all the files and the names of the files. Some recoveries will allow you to flash an unsigned rom, but you might as well figure out how to sign them. It's in the android link I posted earlier.
Good luck!

Thank you for that also this is very helpful I was kinda confused on where to start with aosp, also that the droid 3 has a locked bootloader
Sent from my DROID3 using XDA App

By any chance would you know how to do some theming? If I understand right it has to do with decompiling the framework-res and systemui apks, and replacing some pngs and xmls with others right?
Sent from my DROID3 using XDA App

I just got started with this so I am by no means an expert. I think you'll want to start by deodexing a rom so that you can make changes to the res, xml, etc. I think most stock apps come as a two part package- an .apk file and an .odex file, both with the same names. Find a stock app and look in the framework and app folders. De-odex-ing takes the odex file, de-compiles it, and then recompiles it into a classes.dex file that is put back into the apk or jar file. This configuration will should allow you to make changes without having to compile the rom from scratch... at least that is my understanding.
Find an apk that doesn't have an odex file and look for the classes.dex file inside. Then take a peak in the res folder in the apk. In the res folder you'll find all sorts of xml and png files.
To get started with decompiling, you'll want baksmali http://code.google.com/p/smali/wiki/DeodexInstructions
Take a look at the issues. JesusFreke wrote some interesting comments in issue 61.
I think there are a few other packages that will do the same thing, and there are certainly a few scripts that will work too.
I ran into some issues with deodexing honeycomb- I outlined the process here http://forum.xda-developers.com/showthread.php?t=1324653.
This is also a good source http://wiki.sdx-developers.com/index.php/How_to_deodex_a_ROM

Good info, thanks.

thank you you have been extremely helpful, im gonna try to get my rom out by sometime this week thank you

I just did some mini-theming. I have an ASUS Transformer- the stock rom has it's own back/menu/home buttons. I wanted a more complete honeycomb look, so I grabbed the stock honeycomb versions from a xoom rom, and added them into my deodexed stock ASUS SystemUI.apk. Oddly enough, if I signed the apk, it wouldn't work, but if I left it unsigned, it works fine.

thats odd, i thought you needed to sign it for it to work

HELP with Decompiling APK (using APKTOOL)

I've looked around for some good tutorials on decompiling APKs using APKTool but haven't been able to get a few questions answered. Hoping someone can guide me with this process a bit since I'm really new at it.
A few things first: I am running CM 7.1 on a Droid Incredible (orig) and I'm also on Windows, not Linux. I'm looking to make some changes to the code of an APK and have APKtool downloaded. Questions I have so far are:
1) Do I need to use the CM 7.1 framework-res.apk file for any decompiling / /recompiling work on this 3rd party APK? Or can I do all the work without it? No one seems to have a clear answer on that and I'm not sure exactly what the framework-res.apk is for exactly.
2) After I decompile an APK and make code changes to a SMALI file, is there anything I need to do special before running the compile command?
3) After I have a newly compiled APK, what do I need to do to make this work on my phone? If I do nothing, the overall file size of the compiled APK seems much smaller than the original one that I decompiled so it seems like something is wrong. Plus it won't install. I saw one video where the newly compiled APK is renamed to .ZIP and the contents are put into the ORIGINAL APK (also renamed to .zip), overwriting all the original contents. Is this required?
4) I've also read that APKs need to be signed to install on Android. Is this correct? I found "SignApk" online which seems like it just asks you to rename your APK to app.apk and it does the signing by running a .BAT file. Is that all I have to do before installing the APK on my phone?
Would really appreciate any help on this. Or if there's a great tutorial out there on doing this, I'd be happy to read through.
Thanks for any help in advance!

I want to know these too! Hope someone helps

Remove Battery Indicator Icon

Is it possible to remove/hide the battery icon? I'm on a Samsung Epic 4G Touch with a stock ROM that's been rooted.
I don't want to replace it with something else (I've already done that). I want to remove it, so it doesn't take up space in the notification toolbar.
Thanks for any help.

you could ask Master&Slave(tm) . as you can see in this thread he made some statusbar mods before and maybe he knows how to do that

there is a tut in second post of this thread:
forum.xda-developers.com/showthread.php?t=1371330
i havent tried it, since my rom has this option built in

t0mas_ said:
there is a tut in second post of this thread:
forum.xda-developers.com/showthread.php?t=1371330
i havent tried it, since my rom has this option built in
Click to expand...
Click to collapse
^^^I second this^^^
I have previously used this method on the t-mobile sgsII. Worked great!

I tried following that exact post last night, but I ended up with a missing status bar. The issue I'm having is that none of the instructions I've seen are for an odexed system. I'm running the stock rom, so all my .apk files have corresponding .odex files, rather than containing a classes.dex file within the .apk file. I'm not sure, but I suspect this could be the reason I haven't gotten it to work.
Basically, I'm doing the same thing as the instructions say, but instead of extracting classes.dex from the SystemUI.apk, I'm using SystemUI.odex, since SystemUI.apk doesn't contain classes.dex. I baksmali SystemUI.odex file to extract the code, modify the code, then smali it back into a new SystemUI.odex, and replace the existing SystemUI.odex with the new one.
Any reason why this shouldn't be working? One possible error that I thought of is that I think I pointed smali to one level too far up in the code directory structure when generating the new SystemUI.odex. Using baksmali produced "out/com/android/systemui/...". In the smali command, I used "out/com", but I think I should have used just "out". I'm going to try again tonight and see if that was the problem. Otherwise I'm out of ideas.

i dont think it is possible to edit odexed apks. not sure though...

How to changeout camera apk in roms.

I'm interested in flashing the Sabsa Prime rom, http://forum.xda-developers.com/showthread.php?t=1839004 , but there are currently reported issues with the camera not working correctly. It's said (by the dev himself) that you can change the current camera apk with a previous one but I'm not exactly sure how to do this. I already have the camera.apk from the earlier version that works great, can I just extract the current rom and replace the camera.apk with the working one and rezip it as a .zip file and flash it? Or would I need to do something else to make it flashable or a different step all together? Thanks!

That sounds about right. Just keep the originals in case there are additional steps. Flash and test.
However, using that other cam apk, if it's the one I'm thinking, not sure if it's allowed. For personal use without re-distributing it, maybe but not quite sure.
Sent from a dream.

Unzip replace and rezip. I do this with all roms I use. There are apks I like to add and delete as well as system audios and bootani. You can alter the rom to your liking just remember not all apks work for a rom in other words you can not use sense apks on a aokp rom for example. And second if you do alter a rom you can not ask the Dev for help if something goes wrong with it, you altered it. With that said alter at your own risk and enjoy the learning.
Sent from my Ice Cold Inspire 4G

[Q] Pushing modified framework-res.apk?

Hi, I'm trying to modify /system/framework/framework-res.apk (on the stock Samsung Oreo ROM), more exactly config_locationProviderPackageNames in res/values/arrays.xml so that I can add org.microg.nlp as location provider. I've used the latest apktool (2.3.4) to unpack and repack the apk. I'm replacing it from TWRP and I checked that it has the same owner and rights. And after rebooting the device never finishes booting up (stuck at Samsung logo and blue led).
If I boot back to recovery and put back the original framework-res.apk the system boots fine.
What else do I need to do to make it accept the modified framework?

hey
Are you ONLY modifying the apk?
I would say there is a lot of things to check. It could be that the apk is being rejected by your handling of it. Compare both versions by 7zip lz4 without extracting. Try and use the best tools during the process.
Also more than likely you're conflicting with a service or permission that a perfect apk can't fix.
Have you tried a search in your ROM to see if any files might be associated with the result you want?
Stuff like...
com.android.location.provider.jar
com.android.location.provider.odex
com.android.location.provider.xml
Try doing all the work from your phone without any windows apps. FX explorer and symlink the apk.
Now that everything I said was probably wrong, someone else can tell you how. I'd try fx and symlink, though. It may just align the planets for you

I'm only modifying one XML resource file, but I don't know what else apktool is doing to the apk.
I'm replacing the original framework-res.apk from TWRP, by cat-ing the modified apk over the original, and I've double checked that the ownership and permissions are unchanged.
I guess I can try using another unpack/repack tool and see if it turns out any better, but I've been told that apktool is as good as it gets.
Perhaps it's because the ROM expects the apk to be signed with a certain key? I don't suppose that the key used by Samsung is available somewhere inside the ROM is it?

​
wirespot said:
I'm only modifying one XML resource file, but I don't know what else apktool is doing to the apk.
I'm replacing the original framework-res.apk from TWRP, by cat-ing the modified apk over the original, and I've double checked that the ownership and permissions are unchanged.
I guess I can try using another unpack/repack tool and see if it turns out any better, but I've been told that apktool is as good as it gets.
Perhaps it's because the ROM expects the apk to be signed with a certain key? I don't suppose that the key used by Samsung is available somewhere inside the ROM is it?
Click to expand...
Click to collapse
@wirespot - Did you ever solve the problem you described in this thread?

Not really. My last attempt was to use Runtime Resource Overlays (RROs) to override certain framework values in order to allow org.microg.nlp to run side by side with Google's service.
I will provide them below but it ultimately didn't work. The RRO apk was installed correctly, I could access the NLP settings in the system settings but the main app still could not detect or connect to the service and none of the apps that use location would work.
If anybody else wants to build or use the RRO apk I'm attaching the relevant files as well as the apk. Please note that the built apk only has "org.microg.nlp" as service in arrays.xml (but I provide an arrays.xml with all three services).
apktool.yml is provided as txt file because it wouldn't let me upload it otherwise, remove the .txt. It's used if you build the package with apktool. Remember that you'll also have to generate your own certificate and sign the package in order to install it.
Also some links that may help:
https://forum.xda-developers.com/t/guide-how-to-make-gsis-overlay-file-for-your-phone.3878974/
https://github.com/ReinhardStrauch/framework-res-overlay-sample
https://android.stackexchange.com/questions/110927/how-to-mount-system-rewritable-or-read-only-rw-ro
https://source.android.com/devices/architecture/rros#configuring-overlays
https://source.android.com/devices/automotive/hmi/car_ui/appendix
https://source.android.com/devices/automotive/hmi/car_ui/rro#step_6_dump_the_idmap
https://dzone.com/articles/customizing-android-devices-using-the-runtime-reso
https://dzone.com/articles/android-solution-install-parse-1
https://stackoverflow.com/questions...s-not-recognized-internal-or-external-command
https://github.com/lineageos4microg/android_prebuilts_prebuiltapks/issues/22

wirespot said:
I guess I can try using another unpack/repack tool and see if it turns out any better, but I've been told that apktool is as good as it gets.
Click to expand...
Click to collapse
For decompiling and building Android Oreo, I prefer version 2.3.1 of APKTool to other versions of APKTools.
wirespot said:
I'm only modifying one XML resource file, but I don't know what else apktool is doing to the apk.
...
Perhaps it's because the ROM expects the apk to be signed with a certain key? I don't suppose that the key used by Samsung is available somewhere inside the ROM is it?
Click to expand...
Click to collapse
wirespot said:
Hi, I'm trying to modify /system/framework/framework-res.apk (on the stock Samsung Oreo ROM), more exactly config_locationProviderPackageNames in res/values/arrays.xml so that I can add org.microg.nlp as location provider.
What else do I need to do to make it accept the modified framework?
Click to expand...
Click to collapse
I have not tried modifying framework-res.apk of a Samsung Android Oreo nor have I particularly tried the location services mod you are attempting (though I might get around to trying it someday) and do not know if it is valid to to accomplish what you want with it, but believe that the process should be similar to modding the file on LG Android Oreo. I shall try to guide you to how to prepare a framework-res.apk that is proper.
To answer your question about expecting a certain key. The answer to that is that that is usually the case. The signing scheme checks on system apps; however is usually not as thorough as non-system apps. framework-res.apk is also special in that it is not a running app and is instead used as a cache of system resources and system meta information. In the past, before Android Oreo, a rebuilt framework-res.apk may be made to work simply by including original signature files (META-INF) and corresponding AndroidManfest.xml file from the original framework-res.apk into the rebuilt fraemwork-res.apk file. The system would evaluate these files, and pass a check for valid platform signature. With Android Oreo, it appears that there is an additional check that was not present in the past; my best guess is that the system is checking for the V2 signing scheme signing block within the V2 Signing Scheme APK file structure. The check does not, however, thoroughly validate the signing block information.
Your mod seems rather simple and, given your previous posts, would only involve a modification to framework-res.apk "resources.arsc" member file (which contains the compiled "res/values/arrays.xml" file). If the rebuilt "resources.arsc" can be used to update ("Update" is an actual ZIP archive operation) the original framework-res.apk's member file, the updated framework-res.apk should work (and remained zip-aligned if originally zip-aligned), so long as the packed file size of the updated member file is less than or equal to the packed size of the original member file, plus up to 4 bytes depending on proximity to the next member file data if original framework-res.apk is zip-aligned as expected. If the packed modified member file(s) are larger, the original APK file structure would likely not be preserved, and a different method might have to be used. Also note that 7-Zip is not reasonable software to use for this, despite it being included with many tools on XDA to modify APK files; the software has had a history of rearranging unnecessarily zip file table entries when a change is made to an archive. Use a different tool that does not do this, such as WinRAR (I have tested version 5.61).
For normal apps, one may not copy over "resources.arsc" or resources from two different app builds and have things work correctly when the app runs; one would also need to make corresponding changes in the *.dex APK member files. framework-res.apk, not being an app the runs, has no corresponding *.dex files, and one need not worry about corrupting the relationship between the *.dex files and the resource files because none exists to corrupt.