Often times, we get our brand new smartphones but we don't like all the bloatware that comes along with them. Perhaps we just don't like the look of the UI and would rather have the stock Android experience. Sure you could just buy a Nexus, but maybe you like the device that you have for it's features. The great thing about Android, is that you can easily load on a new custom version of the OS, by way of flashing a custom ROM to your device. I know what some of you might be thinking. "What's a ROM?" Quite simply put, a ROM is a custom version of the Android OS, or otherwise aftermarket Android firmware that has been customized by someone in the development community. There can be many reasons for deciding to flash a custom ROM to your device. If not for the sweet custom experience with added features and cool tweaks made by the developer, at the very least for the fact that it can often times provide you with a stock android experience should you be looking for one. In this little how-to, we're going to walk you through some easy steps on flashing a custom ROM to your device, so if you decide to take the plunge, you'll know where to start. This guide is aimed at helping you complete the custom ROM process as easily and safely as possible, so make sure to go through the entire guide before you start.
Unlocking The bootloader/Flashing A Custom Recovery
Many Android devices come with locked bootloaders, so before moving forward the very first thing you're going to have to do in most cases is unlock it. After this step is done you'll need to make sure you flash a custom recovery. Although you don't need to "Root" your device before you flash a custom ROM to it, (some ROMs even provide root access upon flashing them) it will certainly make the whole experience easier and then some. Since there are so many different Android phones out there, unlocking the Bootloader, rooting, and flashing the custom recovery is pretty much different for all of them. To make sure that you're doing things correctly you'll want to head over to the XDA Developers website and find some useful information about your specific device, and get the correct steps for your particular phone. Some are a little easier than others, and have specific tools to help walk you through the process or even do most of the work for you so long as you have the provided files. I'm speaking more generally for the Samsung devices which can usually use the popular program called Odin to do these processes, and Nexus devices which have the very hand Nexus Root Toolkit provided by the savvy WugFresh, a dev found on XDA. Past these two, the process to unlock the bootloader and get the custom recovery on your phone is pretty vast, so we can't really go into specifics. We can however recommend a couple custom recovery's for you, as they are the most popular and provide some of the best features. When ready to find the custom recovery tailored to your phone model, you'll want to find either TWRP(Team Win Recovery Project), or ClockworkMod Recovery, both of which can be searched for via Google or also found on XDA.
Backing Up Your System And Important Data
Next, before we move onto ROMs and anything else, you'll want to make sure to create a backup of the system image, this way if the whole entire process takes a turn for the worst you'll have a backup of the OS in a safe state before the issues arose. Since you now have the custom recovery, you'll be able to boot into it and flash the safe backup image should things go wrong. Also, just to be clear, this backup process does not have anything to do with backing up any of the data you had on your device prior to unlocking the bootloader, rooting, and flashing the recovery. Unlocking the bootloader WILL wipe your device, so make sure to do a backup of anything important that you don't want to lose. (I.E. photos, music, notes, apps, etc.) Moving on, to achieve the backup of your system, referred to as a "Nandroid Backup", you'll have to boot into recovery mode, which is usually accomplished by pressing a series of hardware buttons simultaneously. The exact set of buttons you need to press to enter recovery is different from device to device, so be sure to make note of which buttons you need to press to get there. It should go without saying, but your device also needs to be "off" for you to boot into recovery using the hardware keys. Once you're in recovery mode, navigate to the backup section and proceed to commence the process. The backup of the system image can take quite some time, so use this little bit of free time to collect your thoughts, think about your favorite movie, or even make a sandwich while you wait. When it's all over, you'll feel rewarded for having gotten this far without breaking something, and you'll no longer be hungry! As unlocking the bootloader will usually wipe your device, and since that's the first step to this guide, backing up your app, and app data isn't really necessary at this point in time, but at some point in the future should you be switching custom ROMs, you can use an app like Titanium Backup to do all the app+data backups you need so you don't lose a thing. Titanium Backup doe's require root access, so make sure you're rooted before you attempt to use it.
Finding, Downloading, And Flashing Your Custom ROM
Now the fun part, it's time to download and flash your custom ROM of choice. The ROM community has come quite a long way since the early days of Cyanogenmod, (which was really the only custom firmware when it first released) and there are now many different custom ROMs available for your choosing. Some devices have many more ROM options than others, but the most popular ROMs usually have a build for just about anything. Once again, XDA is a great place to look if you want to find out what's available for your device and often provides you with the downloadable files you'll need to complete the ROM flashing process, ROM included. Some of the most popular ROMs available currently are of course, CyanogenMod, and also the Pacman ROM, AOKP, and Paranoid Android, just name a few. Many of these ROMs offer lots of custom UI tweaks and features that the stock version of Android nor the manufacturer version have out of box, and there is a flavor to suit just about every taste. Whether you want something completely minimal with a few minor additions, or you want complete customization with all kinds of new features, you can more than likely find something that you'll love.
CyanogenMod and Paranoid Android are a couple of our favorites if you want a place to start. Once you find the ROM you like, make sure to download and eventually place it in the main directory of your internal SD card so you can get to it when you're ready to flash. The downloaded ROM file will be in the form of a .ZIP, and this is what you want so don't worry about unzipping it before you begin. Once you have the file in the correct place, (you can do this a couple ways. Either by connecting your phone to your computer and navigating to your phones storage drive, or by using a file manager app directly on the phone if you have downloaded the ROM .ZIP file using your phone's browser. If you're using a file manager, ES File manager, and Astro are a couple excellent choices) it's time to boot back into recovery mode so you can begin the steps to flash the custom ROM.
Once in recovery mode there are few things you'll want to do before you actually flash the ROM. First, it's a good idea to wipe the dalvik cache(although not usually required), and then move on to completing the step "Wipe data/factory reset". If you're using the latest ClockworkMod Recovery, wiping the dalvik cache option will be located under "advanced settings". Navigate to advanced by using your phone's volume keys, then hit the power button to execute. Under advanced, wipe dalvik should be the fourth option down. Navigate to it and hit the power button to execute. When that's all done,(which should only take like 10 seconds or less) get back to the main menu by navigating to the "go back" option and hit the power button. Once on the main menu, the "wipe data/factory reset" option should be the third option down. Navigate to it and hit the power button to execute. There's no going back from here, so hopefully you made all the backups you needed. The wipe process usually only takes a minute or so.
Once the wipe has completed, the next step is to navigate to "install .zip from SD card" and hit the power button. Next, you'll want to navigate to "choose .zip from SD card" and hit the power button again. If you stored the ROM in the correct directory, (the main directory of your internal SD card) you should be able to scroll and find the package file name of the ROM. Navigate to it, then hit the power button to begin the install. The install process will probably take at least a few minutes, and once it's done you can navigate back to the main menu of the recovery and hit reboot. The first time you reboot your device after flashing a custom ROM, the boot process usually takes a little longer than normal, and sometimes several minutes, so don't be alarmed. This is normal. If starts to bootloop, something in the process went wrong, (usually forgetting to wipe data is a commonly missed step)This can also be specified in the ROM information when you go to download the ROM file. Once all booted up, you're almost done, theres just a couple more steps.
Flashing The Gapps Package For Play Store Access And Google Related Apps
Flashing a custom ROM can give you all sorts of fun new tweaks and UI features, but ROMs don't come with the play store or google apps installed. This is why you have to flash the Gapps package file. This is a fairly simple process, especially since you've come this far. All you have to do is find and download the correct Gapps package file for your Android version and flash it the same way you flashed the ROM. You can find the correct Gapps package many places on the web, but the simplest way to this is one of two ways. Find the right file via XDA, or you can download and install an app called Gapps manager to help identify and locate the correct file of Gapps to download, (you can find and download Gapps manager here)Once you have the right file, place in the main directory of your internal SD card just like you did the with the ROM, and reboot into recovery mode to flash it. When flashing the Gapps package file, you do not have to wipe your data. Just navigate to install zip from sd card, then to choose zip from sd card like before and flash. Once that's done, reboot your device and you're good to go. That's it! Now you can start playing with your new ROM and customizing everything to your liking. We hope this helped you understand the process on how to flash a custom ROM if you weren't already aware of how to do so, and maybe even spark your interest in flashing ROMs in the future. As always, you assume full responsibility for doing any of the above processes to and we nor the devs are liable should anything happen to your device. That being said, if you follow all the instructions to the letter, you should be perfectly fine. Happy Flashing!
Source & Image Credit: Lifehacker