How to build an A12+ ROM from scratch under Ubuntu 22.04 (or based) and higher

BuildGuide.txt

To build a A12+ (AOSP/LOS based) on Ubuntu 22.04+ (or distros based on it), there are four main steps:
(This guide is applicable for recoveries as well (TWRP, OFRP...))
Working on Android 12 and upper
 
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#                  Step 1: Setup your environment               #
#################################################################

****Setup Linux to build Android****

sudo apt update && sudo apt full-upgrade && sudo apt install build-essential ccache libncurses5 libssl-dev m4 unzip zip brotli bc bison curl flex g++-multilib gcc-multilib git gnupg gperf imagemagick lib32ncurses5-dev lib32readline-dev lib32z1-dev liblz4-tool libncurses5-dev libsdl1.2-dev libxml2 libxml2-utils lzop pngcrush rsync schedtool squashfs-tools xsltproc zip zlib1g-dev adb fastboot python-is-python3 abootimg git-lfs libwxgtk3.0-gtk3-dev

If you use a Linux distribution based on Arch, use this instead: https://github.com/akhilnarang/scripts/blob/master/setup/arch-manjaro.sh

****Setup repo****

git config --global user.name "YourName" && git config --global user.email "[email protected]" && git config --global credential.helper "cache --timeout=7200"
mkdir ~/bin && PATH=~/bin:$PATH && curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo && chmod a+x ~/bin/repo (<- this command requires a reboot to apply properly on the user's path).

The credential helper's cache saves you logging in each time you want to push your trees to GitHub, and the name and email will appear in the signature of your commits whenever you use the --signoff in your commit command (git commit -m "Example of commit" --signoff)

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#               Step Two: Download the source              #
############################################################

****Create a folder for your source****

mkdir foldername && cd foldername

When you want to build a ROM, you must download its source. All ROMs will have their source code available on GitHub. To properly download the source, follow these steps:
-- Go to your ROM's Github (e.g. http://github.com/crdroidandroid)
-- Search for a manifest (usually called manifest or android_manifest).
-- Go into the repository and make sure you are in the right branch.
-- Go into the README file and search for a repo init command. 
   Tip: adding —-depth=1 between repo init and -u in order to make a shadow clone of the source (will reduce drastically the space used).
   Paste it into a terminal under the folder you've just created and hit enter.
-- After the repo has been initialized, run this command in order to download the source properly:
   repo sync --current-branch --no-clone-bundle --no-tags --optimized-fetch --prune --force-sync -j$( nproc --all )
-- This process can take a while depending on your internet connection. Go and have a beer/coffee/nap/the whole day in the meantime! The whole ROM source can take ~90 GB of your disk (a SSD is always recommended).

###########################################################################
#                  Step Three: Download the device trees                  #
###########################################################################

In the ROM folder, there is a hidden folder called .repo.
So, to be able to download the device trees: 

cd .repo
mkdir local_manifests && cd local_manifests
nano zbuild.xml

There you will have to create your own manifest with your device's repos (usually three: device tree, kernel and vendor). Take a look at this example:

https://github.com/masemoel/local_manifests/blob/master/picasso_q.xml

NAME means the GitHub repository's name, PATH means where you want the repository to be saved, and REVISION means which branch you want to clone.
Here you have a template:

<?xml version="1.0" encoding="UTF-8"?>
<manifest>
  <project name="masemoel/android_device_brand_codename" path="device/brand/codename" remote="github" revision="11.x"/>
</manifest>

****Save your manifest at zbuild.xml****

Then repo sync --current-branch --no-clone-bundle --no-tags --optimized-fetch --prune --force-sync -j$( nproc --all ) again (it will take much less than the first time, as you already have almost all your source downloaded 😄).

Another way to download the device trees is to git clone each of them, but you will need to update them manually using git pull command. With the local_manifest, they will get updated along with all the ROM repos when you repo sync.

The next part is to setup the device tree created for the specific ROM you want to build. I won't explain you here how to configure your device tree to a specific Android version (for example, if you have an Android 7.1.2 device tree, you cannot build Android 8 or 9 with it; you need some adaptions), so ensure you're cloning the tree/branch for the desired Android version.

To configure the device tree to build a specific ROM do the following (using the Redmi K30 5G, whose codename is picasso, as an example, and explained by aoleary):
1. cd device/xiaomi/picasso
2. nano AndroidProducts.mk
3. replace havoc_picasso.mk to what the ROM requires: <rom_name>_picasso.mk (check the ROM repo for another device to see what they need. For example, for LineageOS, it should be lineage_picasso.mk, du_picasso.mk for DirtyUnicorns,...)
4. Rename the file havoc_picasso.mk to what the ROM requires: <rom_name>_picasso.mk
5. Within <rom_name>_picasso.mk, change everywhere it says "havoc" to <rom_name>.
6. Also verify that the paths are consistent, within <rom_name>_picasso.mk, specially for the variable:
  # Inherit some common LineageOS stuff.
  $(call inherit-product, vendor/<rom_name>/config/common.mk)

==> You need to browse the ROM vendor repo and go and check the file exists with the same name and that the path exists as well. <==

##################################################
#              Step 4. Build the ROM             #
##################################################

NEW! Android 12 and higher needs this workaround to avoid A12 building errors with ccache https://gist.github.com/masemoel/537301229c1bd4c8b20c50f535751d19

Before starting to build, we are going to turn on ccache to speed up the build process by typing in a terminal:
export USE_CCACHE=1 && export CCACHE_EXEC=/usr/bin/ccache && ccache -M xG (where x means X GB of ccache. Anywhere from 25GB-100GB will result in very noticeably increased build speeds (for instance, a typical 1hr build time can be reduced to 20min). If you’re only building for one device, 25GB-50GB is fine. If you plan to build for several devices that do not share the same kernel source, aim for 75GB-100GB.) This is not noticeable for the first build, but it's very helpful for future builds. As far as I know, this ccache is storaged at /home/user/.ccache .

Allocate Jack enough memory:
export ANDROID_JACK_VM_ARGS="-Dfile.encoding=UTF-8 -XX:+TieredCompilation -Xmx#G" (put your GB of RAM where # is).

The following command fixes some compilation issues when building on Ubuntu 18.04 or higher, so this is a must for us:
export LC_ALL=C 

The building commands are usually individual to each ROM. It's within the same README.md from step 2. For crDroid or any other LineageOS-based, they are:
. build/envsetup.sh && lunch lineage_picasso-userdebug

And then, run the building commands for your ROM (again, check the README at the manifest of the ROM; there you will see it. LineageOS uses mka bacon, while for example EvolutionX uses mka evolution).

If you run out of memory on some metalava or ninja steps, you can reduce the number of cores available for the compiler. For so, just add -j x (where x is the cores you want the compiler to use as maximum. Less cores = less RAM) at the end of the building command. Remember that the minimum adviced for RAM is 16GB of RAM (and even with this you might face OutOfMemory errors, though you can increase your swap partition to bypass this).

When the build process has finished, the flashable zip will be saved at /out/target/product/devicecodename

########################################################################################
#                              Success! So... what's next?                             #
########################################################################################

You’ve done it! Welcome to the elite club of self-builders. You’ve built your operating system from scratch, from the ground up. You are the master/mistress of your domain… and hopefully you’ve learned a bit on the way and had some fun too.🥳🥳

****Useful for future builds****

If you've made some important changes ==> . build/envsetup.sh && make clobber (to recompile everything from scratch and avoid weird bugs. Most of the times, you only need to wipe out/target/product/codename).
Keep the source up to date ==> repo sync --current-branch --no-clone-bundle --no-tags --optimized-fetch --prune --force-sync -j$( nproc --all )
For Ubuntu 18.04 users or higher ==> export LC_ALL=C does NOT persist on reboot!!!!
If you have a compilation error and you don't know how to solve it, you can ask here following the rules ==> https://t.me/AndroidBuildersHelp

Take logcat: adb logcat -d > logcat.log
Clear logcat history (it's cleared automatically on each reboot): adb logcat -b all -c

Credits to:
- LineageOS team (as I took some necessary stuff from their guides)
- aoleary (he did the h815 example for setting up the device tree and more)
- nathanchance (this is his guide template)
- masemoel (me)

Hi, can you update this for android 13, if required. It's a great guide.. and I am building for A13 already.. just asking if there is something missing. Btw, can you also add kernel building process which aligns with this article.

Thanks for sharing the knowledge.

This guide works good for Android 13 as well. The only difference I've noticed is that A13 builder takes a bit more RAM.
If you want to add inline kernel source have a look at this if you have prebuilt kernel - masemoel/device_xiaomi_picasso-unified@d55ba2e

Hi, can you update this for android 13, if required. It's a great guide.. and I am building for A13 already.. just asking if there is something missing. Btw, can you also add kernel building process which aligns with this article.
Thanks for sharing the knowledge.

This guide works good for Android 13 as well. The only difference I've noticed is that A13 builder takes a bit more RAM. If you want to add inline kernel source have a look at this if you have prebuilt kernel - masemoel/device_xiaomi_picasso@d55ba2e

Thanks man!

make: Entering directory '/home/greg/crDroid/kernel/xiaomi/msm8953' make[1]: Entering directory '/home/greg/crDroid/out/target/product/tissot/obj/KE RNEL_OBJ' GEN ./Makefile scripts/kconfig/conf --silentoldconfig Kconfig CHK include/config/kernel.release Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not support ed by compiler make[1]: *** [/home/greg/crDroid/kernel/xiaomi/msm8953/Makefile:1241: prepare-co mpiler-check] Error 1 make[1]: *** Waiting for unfinished jobs.... make[1]: Leaving directory '/home/greg/crDroid/out/target/product/tissot/obj/KER NEL_OBJ' make: *** [Makefile:152: sub-make] Error 2 make: Leaving directory '/home/greg/crDroid/kernel/xiaomi/msm8953' 13:59:41 ninja failed with: exit status 1

failed to build some targets (31 seconds)

I don't know how to solve this issue?

I'm not pretty sure about this, but maybe your clang doesn't support CONFIG_CC_STACKPROTECTOR_STRONG. Drop that config or use an specific clang version.

You didn't send the error completely. Please copy and paste the full build log at some paste online service