I know there is no good guide to starting Android custom ROM Development. You can learn about building.

Note: This guide doesn't contain any technical tutorials. This will show you a good way to start your AOSP / Android Custom ROM development journey in a community-oriented way.

1) Get an android device which has good community support

→ I recommend buying a device with a good community if you don't have any prior experience with android modding/custom ROMs.

→ If you have prior knowledge of custom ROMs, you can go for any good device.

→ How to know if a device has a good community? Check Telegram and XDA (More detail in the next point).

Why not an emulator?

You can start learning AOSP (framework, internals) using an emulator but I want you to involve in the android ROMs community and learn from them so the actual device is the best way.

2) Join your device community

→ Nowadays, every device has a community in Telegram. You can find it simply by searching your device name or codename in Telegram.

→ How to know my device codename? A simple google search "<device_name> codename" will do the work.

→ Check XDA Developers Forum for your device forums. There you can find threads (posts) for your device.

Search "<your device name> xda" in google. You can find your device forum easily (only if your device has forums in XDA)

Now you found your device community, what's next?

→ Engage with the community members.

→ Talk more about your device.

→ Get help. Give help

→ Make friends. Make friends

→ Learn from them

Points to remember in a community

→ Don't expect a spoon feed from the community members.

→ Avoid asking things that you can find by a simple google search.

→ No "Hello" and "Hi". Ask your question directly.

→ Prefer the common chat over DM. Seek help in public. So you will get help from more people and others will learn from your convo.

→ Learn to wait. People have their own life to live - value others' time.

→ Be kind to others.

Sound rude or not friendly? Trust me, follow the above points blindly. You will see the magic in your community. You will realize soon why it's important.

3) Use custom ROMs on your device

You joined your device community, Now let's get into the core.

Note: Make sure you know what you are doing.

→ Get the basics of android custom ROM and its related terms like ADB, bootloader, recovery and so on.

→ Unlock the bootloader

→ Install a custom recovery

→ Flash a custom ROM via recovery

Properly follow the instructions mentioned in the ROM thread/post.

→ Get help from the community. Don't follow anything blindly or your device will become unusable (worst case).

→ Enjoy the perks of custom ROMs. You will love it for sure.

In this phase, Explore custom ROMs and become familiar with them.

There is a lot to mention. But I am sure you will learn all the things eventually from the community.

4) Build a custom ROM for your device

You are a pro user now, let's do something more.

Let's compile an Android ROM for your device.

To build an Android ROM, you need a good specs PC.

Check the requirements: https://source.android.com/docs/setup/start/requirements

Most people (like me) can't have a machine that meets the requirements. I got you.

What you can do about that?

→ Try to get a free trial from services like Google Cloud Platform (GCP), Azure or AWS. Then create a virtual machine (VM)

→ Ask for help from your community friends. They may help you.

Now you have the machine to build.

How to build?

I ain't gonna write it about in detail since there are a lot of guides out there. (a thread for another day)

Lineage wiki (device-specific): https://wiki.lineageos.org/devices/onclite/build Official doc: https://source.android.com/docs/setup/start

From the lineage wiki, up to this https://wiki.lineageos.org/devices/onclite/build#download-the-source-code are common for all devices.

For the next step

→ You have to download/clone your device sources - Device config tree, kernel tree and vendor tree.

→ Lunch your device

→ Start the build

I recommend you get the details from your community. Learn from them. Get help from them. (no spoonfeeding)

Build errors: Try to get help after trying something yourself. Don't go straight to the community without any try. (a thread for another day)

I hope, Now you know how to get started in Android custom ROM development.