Many of you having no doubt heard the term “custom ROM” from time to time, but haven’t really been sure what it is. So far this term applies strictly to Android, and it refers to a customized version of the Android operating system, usually built and maintained by a single hacker, or group of hackers. Your first thought is probably, “how does one person rewrite an entire operating system?” The truth is they don’t, and this is due to the open-source nature of Android.
What OPEN SOURCE means is that the SOURCE CODE (the human-readable script used to compile the finished program) is freely available and anyone is allowed to modify it to their heart’s content. Google of course make the source code for stock Android available, but one can’t just take that code, compile it, and then expect it to run on just any phone. An operating system is the sum of many parts, including what’s known as HARDWARE DRIVERS, which are necessary for the base operating system to communicate with the hardware on a given phone or tablet.
That makes the core source code interesting, but not useful. Fortunately, the same open source license also applies to manufacturers that create their versions of the Android for each device they make. Now that individuals have access to the source code for Android on a specific phone (like, say, the Samsung Galaxy S4 for instance) they can delve into the code and change whatever it is they don’t specifically like about it.
There are too many custom Android ROMs to count, and many of them are relatively amateurish works that are unreliable as “daily drivers”. However, some custom ROM ventures were exceptionally well-run projects right from the start and they grew to become entire multi-programmer projects. The best known of them is CyanogenMod, which expanded to cover just about every popular phone ever manufactured. While CyanogenMod continues in that way, it has risen above amateur status recently and has become the official version of Android by at least one Chinese manufacture. That required their version of CyanogenMod getting official Google certification.
So fine, what does a custom ROM do for you? Usually they are stripped of all of the bloatware commonly crammed into phones by their manufacturers that make them sluggish. Many are distilled to the point that they closely resemble the true Google Android experience as you can get. They also add thoughtful touches that were left out of official versions (like the ability to rotate the screen to 180...
However, their real claim-to-fame is they allow owners of older (and now unsupported) phones to keep up with the latest releases of Android. CyanogenMod is now based on version 4.4.2 of Android (that’s KitKat) and you can install it on a huge array of different phones, many of which have long since been ignored by their manufacturers (meaning no future releases of Android will ever come out for them via official channels).
However, installing a custom ROM is not for the faint-of-heart and requires that you have a rooted phone. This means that you really need to have some experience with hacking phones, which puts it out of reach to most smartphone owners. Organizations like CyanogenMod have tried to overcome this limitation by producing the closest thing to a one-step install (including the rooting process) that you can get. For a short time this one-step installer was even available on Google Play, but alas it violated certain terms of the store and had to be removed. You can however download the installer directly from the CyanogenMod web page.
As a means to prolonging the life of orphaned phones and tablets (which are still powerful enough for many people) the customer ROM community has demonstrated that their wares are more than just a toy for other hackers to play with. If you own an orphaned phone and are upset that it’s stuck on an out-of-date version of Android, then you might want to look at trying a custom ROM instead of spending the money on a new phone. If you don’t have any experience with doing this, then go directly to www.cyanogenmod.com and see if they support your phone model.
Shortly before I posted this article I dug out my old Samsung Galaxy S Captivate, which I bought back in December of 2010. It was one of the original Galaxy S phones, with a single-core 1 GHz processor and 512 MB of RAM. I haven’t used it in ages and it has long since been abandoned by Samsung. The last official version of Android it ever got was Gingerbread. I downloaded and installed CyanogenMod 11 (Android 4.4.2 KitKat) on this phone and it works very well. The phone is still slow due to the less-than-optimal processor and minimal RAM, but it runs much more smoothly than it had under Gingerbread. Below is a screenshot of the About screen on the Captivate. Note the model number (SGH-i897) and the version of Android (4.4.2).