Android ROM explained

There has been a lot of talk about Android ROM and how to flash it with a custom ROM to bring new features to your smartphone. People are also talking about rooting an Android OS and installing aftermarket firmware on it. In the world of Android, the word ROM which stands for Read-Only Memory is being misused. A better term would be "firmware" where the binary image of Android OS is installed. Let's start out by defining a few terms used in the Android world.

Stock ROM - A stock ROM is a firmware that comes with your phone which is customized for your carrier by the manufacturer. It has Android OS on it with carrier-installed bloatware that purposely imposes limitations on the phone unless users pay for those restricted features.

Custom ROM - A custom ROM is a firmware customized by Android developer(s) to offer more features, increase performance, and remove carrier-installed bloatware. It is generally a modified version of a Stock ROM with an upgraded Android OS, Linux kernel, performance-optimized apps, and stripped bloatware firmware.

What is Rooting? - Rooting your phone is getting an administrative right to your Android OS. Android is based on Linux, and the "root" is the administrative user of the Linux OS. Having root access to your device grants you complete control over your phone. Rooting does NOT mean installing a custom ROM, as you can gain root access to a Stock OS. By rooting your OS, you install Superuser Android app, which approves or deny administrative access to your device instead of conventional password protected approval. One word of warning about rooting your phone is that it could potentially brick your phone and void the manufacturer's warranty. See How to root your Android OS for more information about rooting your device.

Why would you install custom ROM on your smartphone?

1. One of the primary reasons for installing custom ROM on your smartphone is to upgrade an Android OS. The carriers and manufacturers go through a rigorous process to make a new Android OS available for a smartphone, and some of the older phones will never be upgraded to the most recent Android OS. At the time of this writing, most phones have Android 2.3.x (Ginger Bread) installed on it, and although Android 4.x (Ice Cream Sandwich, or ICS for short) was released more than 7 months ago not many Android smartphones support ICS. Android developers work from a leaked version of Stock ROM, or port a ROM from another version of Android phone.

2. The second popular reason for installing custom ROM is to store apps on an SD card. Many Android phones come with very limited internal memory (typically less than 1GB), and it makes it hard to install all the smartphone apps you want on your phone. Check out Comparison of Android Devices yourself to see how much internal memory your phone came with. Most custom ROMs available today have the A2AD which allows you to install Android apps on an SD card.

3. The other reasons for installing custom ROM may include increased performance, increased battery life, and an ability to remove or freeze bloatware with pre-rooted ROM. The reasons may be endless, but you may want to do your homework and decide whether you'll really need to root or install custom ROM on your phone; as doing such activities voids your phone warranty and may potentially brick your phone.

Android Glossories

Bloatware: Bloatware is an application preinstalled by carriers and handset manufacturers that you cannot remove without rooting your smartphone. To remove bloatware from your smartphone, first root your phone and use Android apps to remove or freeze the bloatware.

Brick: per wikipedia, a "brick" describes an electronic device such as a smartphone, game console, router or tablets that owing to a serious misconfiguration, corrupted firmware, software or a hardware problem, can no longer function.

Custom ROM: Custom ROM is a customized or upgraded version of Android firmware made available by Android developers which enhances performance and generally includes features that not not yet available on the Stock ROM.

Defrosting: Defrosting is the process of unfreezing an Android app. See also Freezing.

Freezing: Freezing an Android app refers to disabling an app from opening or running while an app is still installed. Many stock ROMs come with bloatware, and you as a "rooted" owner may freeze the app from running it again.

Rooting: Rooting an Android is getting an administrator privilege on the phone, which allows a user to install virtually any app including free wifi hotspot.

Stock ROM: Stock ROM is an Android firmware developed for carriers by a manufacturer that comes with your phone.