Customization is one of Android’s greatest strengths and there is virtually no limit to it as long as you have the time and imagination. Hell, you can just change the original firmware your Android device came with for a completely different one available quite easily. What more could a customization geek wish for? If you’re familiar with Linux, ROMs are kind of like the different Linux distributions. Each of them is trying to do its own thing with the OS. Admittedly, there isn’t that much of a variety in all the AOSP based Android ROMs compared to the various Linux distributions. But that has only benefitted customization since it gets easy for someone to develop a universal theme engine. Custom ROMs have many benefits which are why we’re going to show you how to install a custom ROM.
Download a ROM & Gapps
Don’t tell me you didn’t see that coming. Luckily, thanks to websites like xda-developers.com finding custom ROMs for your device is not really that hard. Just go to your Android device’s Settings and scroll down all the way to find the About phone/tablet entry. Tap on it and check your device’s model number.
Go to xda-developers.com and search for your specific model number to find a dedicated subforum for it which will have all sorts of ROMs and other stuff. Make sure the ROM you download is compatible with your specific device model number. Many devices have several variants but the same name so you have to be careful about that. The ROM is usually a zip file and could be anywhere from 250MB to 2-3 GB in size.
Most AOSP based custom ROMs do not include any Google apps or services so you’ll have to download them separately. Depending on the Android version the ROM is based on, you can find a Gapps package on opengapps.org. For instance, if the ROM you downloaded is based on Android 7.0 Nougat, download a Gapps package for Android 7.0. You’d also have to keep in mind your device’s processor architecture. (ARM/ARM64/x86)
Unlock bootloader and Install TWRP
Most modern smartphones ship with a locked bootloader for security purposes. Most modern smartphones also have an unlockable bootloader and unlocking it opens the door to custom ROMs and recoveries. The unlocking procedure is a little different for devices from every manufacturer. You’ll have to google how to unlock xyz device and you’ll most probably find several guides, even official ones from the manufacturer itself. What’s common across all of them though is that unlocking your bootloader will most likely wipe your phone. Without root access, you won’t be able to back up very much so just back up what you can like messages, call logs, files on your internal storage, etc.
With the bootloader unlocked, it’s time to install a custom recovery. A custom recovery is the most common way to root your phone and flash custom ROMs and other mods. These days, you’re most likely to find a TWRP recovery for your device than anything else. You can find an official TWRP image file for your device on the TWRP website. Thousands of devices are supported by unofficial builds of TWRP which you can find on your device’s subforum at xda-developers.com as well.
Once you have the recovery image, you’ll need to set up ADB and Fastboot on your PC to flash it onto your Android device. Google how to boot your specific Android device into fastboot mode and then boot it into fastboot mode. Move the TWRP image file into the ADB installation folder. Now connect your Android device to your PC in fastboot mode and then launch ADB. In the ADB command window, type the following command and hit enter to flash the recovery to your device.
fastboot flash recovery twrp.img
Replace the text in green with whatever the name of the TWRP image file is. It’d be better if you rename the file beforehand to something simple such as twrp.img.
Flash custom ROM
ROM, check. Gapps, check. Unlocked bootloader, custom recovery, check. Backup important data… hmm. Well, flashing a custom ROM is fun and all, scary even for first timers and it should be. Flashing stuff from non-official sources can, after all, damage your device and in some cases leave it useless as a brick. Some people call it bricking but bricking is a strong term. In most cases, you can always recover the device by flashing the stock firmware. But that can be a hassle in itself which is why TWRP recovery allows you to take a full backup of your current system and data (excluding internal storage). This way, if your device fails to boot or you are not satisfied with the custom ROM experience, you can always go back to how things were.
- To create a Backup, boot your device into recovery mode. This is a bit different on every phone, but usually, involves some permutation of pressing the power and volume buttons at the same time. You can easily google it just like you did for the ROM and TWRP.
- In the TWRP recovery menu select Backup, then select all the partitions you’d like to back up. Swipe at the bottom and the process will start. Depending on the read/write speed of your device’s storage and the size of the firmware and apps installed, the backup process can take really long. But once it’s done you can be sure that there’s something to come back to.
- If you downloaded the ROM and Gapps on your PC, now would be a good time to transfer them to your phone via a USB cable. TWRP allows an MTP connection when the cable is connected.
- Select Install and select the ROM file. Tap Add more zips and then select the Gapps file.
- Swipe at the bottom to flash the files.
- Once complete, tap on the Reboot system button that appears at the bottom.
Now when your device boots up, you should most probably see a new boot animation, and a fresh new ROM would be waiting right behind it. First boots always take a while so don’t worry if it takes longer than usual. While most custom ROMs can be flashed using the method described above, there can also be exceptional cases which require a specific set of steps to be taken. In such cases, the developer will likely specify the procedure himself.