If you have been around a group of Android tech enthusiasts or geeks, you must have heard the term Custom ROM thrown around. Much as the majority of people using smartphones use Android Operating System, majority don’t get deep into understanding what these terms mean and are normally left out when others start talking about them.
Android devices we use come with a system they run out of the box and this is basically what we refer to as Stock ROM. It is the default system provided by the manufacturer and what that manufacturer thinks is best for it’s users. But not many people end up liking this stock system mostly because systems provided by manufacturers are limited in functionality or their user experience do not appeal to majority of users, or they simply want to upgrade to a higher Android version that Custom ROMs normally provide. These users then opt for different systems for their phones.
A Custom ROM is that modified system built by an individual or company to be installed on a particular phone model to completely replace the stock system. Custom ROMs can come in two ways; those build basing on Stock system (modified stock –look like stock) and those completely different from stock. Let’s mention a few of these popular custom roms so we get the picture.
This is by far the most commonly known of all Android custom roms. It’s built by Cyanogen having it’s source code similar to Google Android source code. Matter of fact, Cyanogen only releases a new version of Cyanogenmod after Google has released a new version of Android. Cyanogenmod is that other go-to generic system that offers more functionality and far easily customizable than stock or Google’s Android itself. It grew way popular to the extent that manufacturers like OnePlus (When it released the OnePlus One), Micromax and now Alcatel among other opted to use it as stock rom for some of it’s phone models.
Cyanogenmod is based on the foundation of customization and you will most likely find the system pre-rooted once installed. The other cherished feature within Cyanogenmod is the Theme Engine. This allows different themes built by different people to be applied to Cyanogenmod to completely theme all elements within the system to give it a complete new look.
MIUI:
This is actually system firmware for phones built by Xiaomi. Xiaomi as a company has grown popular and it’s system has been adopted by many to be used on other phones that are not made by Xiaomi. MIUI gets it’s inspiration from Apple’s iOS. It looks similar to iOS in terms of experience. It looks clean and refined and will perform differently from most used Android systems. MIUI originates from China.
AOSP:
Android Open Source Project (AOSP) is that other bare-bones pure Android software without any added files or application that suit a particular manufacturer. Google uses this to make it’s refined Android that adds Google Services and Apps to make it a more usable experience for majority of regular users. Other manufactures who may not wish to use Google’s Android use this to make their own modified Android systems. Regular users may however prefer to use AOSP in it’s pure form on their Android phones. Similar to Cyanogenmod theme engine, AOSP uses it’s  component called Layers that work similar to Cyanogenmod themes.
This is that other Android version that is a mixture of AOSP and a few Cyanogenmod features like the Cyanogenmod theme engine. In 2015 OnePlus hired the Paranoid Android team to build OnePlus’ current Oxygen OS which slowed down builds of Paranoid Android but in 2016 the team promised to embark on their original mission to build this ROM for various phone models and we’ve seen new builds of Paranoid Andorid based on Android 6.0 Mashmallow for the Nexus 6P, Nexus 5X, Nexus 6, Nexus 5, Nexus 4, Nexus 7 2013, Nexus 9, OnePlus One, OnePlus 2, and OnePlus X.
There are many custom roms available but it’s important to note that most of them are based on Cyanogemod or AOSP. Custom ROMs like Ressurection Remix, AICP, Oxygen OS, Hydrogen OS, BeanStalk, LiquidSmooth among others.
