[Android] jackeagle:
Hello Everyone....:D:D

Today I will present you all the ultimate guide for ROM development starting from Source to End.

This guide will be applicable to all devices.

So lets Start :D

What is Android? :rolleyes:

Android is an open-source operating system developed by Google for smartphones, tablets, and other devices. It provides a user-friendly interface and supports a vast ecosystem of applications through the Google Play Store. With its Linux-based foundation, Android enables multitasking and offers extensive customization options for both manufacturers and users. Its integration with Google services enhances functionality and connectivity, making Android a popular choice for mobile devices worldwide.

Full Freedom for people using it :D

What is Android Source Code?

Android is an open-source software stack developed for a diverse range of devices with varying form factors. The primary objective of Android is to provide an open software platform that is accessible to carriers, original equipment manufacturers (OEMs), and developers, enabling them to bring their innovative ideas to life. The goal is to create a successful, real-world product that enhances the mobile experience for users. One of the notable features of Android is that it offers a complete, production-quality consumer product with source code that is openly available for customization and porting.

Android allows for extensive customization and enables developers to create new functionalities and experiences without significant restrictions. This openness fosters creativity and empowers developers to tailor Android to suit their specific needs. It also encourages collaboration within the Android community, where developers can share their enhancements, contribute to the platform's evolution, and address any issues or bugs.

So basically Android Allows to customize the things you like and make new things without any Restrictions. Cool isn’t it? :cool:

What is Android ROM ?
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An Android ROM refers to a customized version of the Android operating system that is installed on a device. ROM stands for "Read-Only Memory," which originally referred to firmware stored in a device's memory. However, in the context of Android, a ROM typically refers to the software package that includes the operating system, user interface, and other components specific to a particular device or a modified version of Android.

While it is true that an Android ROM includes the user interface (UI) and the file system for maintaining contacts and other data, it is not limited to those aspects. The Android ROM is built upon a Linux kernel, which serves as the foundation for the operating system. Additionally, the ROM includes various system-level components, libraries, and apps that provide specific functionalities and features.

ROMs can be developed by device manufacturers (such as HTC, Samsung, or LG) to provide a customized user experience on their devices. They often come with a unique user interface overlay, such as HTC's Sense UI or Samsung's One UI, which can offer additional features and visual enhancements.

Moreover, ROMs can also be developed by third-party developers or communities, known as custom ROMs. Custom ROMs are modified versions of Android created by independent developers or enthusiast communities. These ROMs are typically designed to offer additional features, customization options, improved performance, or compatibility with older devices that may no longer receive official updates.

What does a Android Rom Contain ?
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Basically a Android Rom Contains following main things:

Kernel: The kernel is the core of the operating system that manages system resources and facilitates communication between hardware and software.

Bootloader: The bootloader is responsible for initializing the device's hardware and loading the operating system into memory during the boot process.

Recovery: The recovery is a separate bootable partition on the device that allows for system maintenance, installation of updates, and performing backups or restores.

Radio: The radio refers to the software responsible for managing the device's wireless communication, including cellular connectivity.

Framework: The framework consists of a set of libraries and APIs that provide the foundation for application development and interaction with the device's hardware and services.

Apps: Android ROMs typically include pre-installed applications, such as system apps (e.g., dialer, messaging) and other core apps (e.g., calendar, browser), which may vary depending on the ROM.

Core: The core components of the Android operating system, including system services, libraries, and essential system processes.

Android Runtime: The Android Runtime (ART) is the runtime environment responsible for executing Android applications. It converts apps from bytecode into machine code for efficient execution.

Some Basics About Above Terms

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Kernel

The Android kernel is a key component of the Android operating system, serving as the core of the software.

It is based on the Linux kernel but includes modifications and additions specific to the Android platform.

The kernel provides essential functionalities, such as hardware abstraction, process management, and memory management.

It controls the device's hardware resources, including the CPU, memory, storage, and input/output devices.

The kernel manages drivers that enable communication between the operating system and hardware components.

It facilitates power management, optimizing resource usage to maximize battery life.

The kernel handles security mechanisms, such as process isolation and permissions, to protect against unauthorized access.

It enables multitasking by scheduling and prioritizing tasks, allowing multiple applications to run simultaneously.

The kernel supports various file systems, networking protocols, and device drivers to ensure compatibility with different hardware configurations.

Kernel updates are released periodically to improve performance, fix bugs, and address security vulnerabilities.

Bootloader

The Android bootloader is a critical component that starts the boot process on an Android device.

It verifies the integrity and authenticity of the software before loading it.

The bootloader is responsible for loading the operating system kernel.

It initializes essential hardware components, such as the CPU, memory, and display.

The bootloader acts as a security checkpoint, preventing unauthorized modifications to the device's software.

It ensures the device boots into a trusted and secure state, protecting against malware and unauthorized access.

The bootloader provides a means to unlock the device for advanced customization and firmware modifications.

Bootloader unlocking allows for installing custom ROMs, kernels, and recovery images.

Some devices have locked bootloaders by default to maintain system integrity and prevent unauthorized modifications.

Recovery

Android Recovery is a built-in feature that provides a separate environment for system maintenance and troubleshooting.

It is accessed by booting into recovery mode, usually through a combination of hardware buttons during device startup.

The recovery mode allows users to perform various tasks, such as applying software updates and factory resetting the device.

It provides a limited but essential set of functions to recover or repair a malfunctioning Android system.

In recovery mode, users can clear cache partitions to resolve performance issues caused by cached data.

It enables users to flash custom ROMs, official firmware updates, and other system modifications.

Recovery mode allows for making and restoring system backups, protecting user data and settings.

It provides a command-line interface (ADB) for advanced troubleshooting and system-level operations.

Recovery mode is separate from the main Android system, ensuring stability even if the main OS encounters problems.

These are main parts of Android Operating System.

Now that we know what Android is and what it contains, let's move on to the next major step, which is Android ROM development from source. However, before starting this process, we need to set up some initial setup and development environment.

Android Rom Development

Setting Up Linux Enviroment

Pre – Requirements for Android Rom Development

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1) Linux Operating System (I will use Ubuntu 13.10 as an example and recommend it to all)

2) Java Development Kit (JDK)

3) Various Tools

Once you have downloaded Ubuntu 13.10, you can install it in two ways:

1) Installing it as the primary operating system

2) Installing it inside Windows using a virtual machine (VM) or virtualization software like VirtualBox (free) or VM Workstation/Player (paid)

3) Dual-booting Linux alongside Windows by creating separate partitions

In this guide, I will explain how to install Linux inside Windows using VirtualBox as an example.

How to Install Ubuntu in VirtualBox

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1. Download and install Oracle VM VirtualBox on your computer.

2. Download the Ubuntu ISO file from the official Ubuntu website or the specific version you want to install.

3. Open VirtualBox and click on New to create a new virtual machine.

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4. Enter a name for your virtual machine, select Linux as the type, and choose the version that matches your Ubuntu ISO.

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5. Set the desired amount of RAM for the virtual machine. It's recommended to allocate at least 2GB or more.

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6. Create a virtual hard drive by selecting Create a virtual hard disk now. Choose the VDI (VirtualBox Disk Image) option and click Next.

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- Select Dynamically allocated and leave the Split into files option unchecked.

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- Specify the amount of HDD space you want to allocate and choose the location for the virtual hard drive (VMDK).

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7. Go to Settings -> System -> Processor and set the desired number of cores for the Guest OS. In this example, we allocate 2 cores.

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8. Now, go to Settings -> System -> Acceleration and make sure both options are selected.

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9. Next, go to Settings -> Storage -> Controller: IDE and click on the small CD with the plus icon.

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- Navigate to the location where you saved the Ubuntu ISO file and select it.

- Click OK to save the changes.

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10. You can now start the virtual machine by clicking Start.

11. The Ubuntu installation process will begin, and you can follow the on-screen instructions to complete the installation.

12. Once the installation is finished, you'll have Ubuntu running in VirtualBox.

That's it! You have successfully installed Ubuntu in VirtualBox.

Hurrrray your Linux System is Ready!​