Beginner’s Guide to Custom ROMs, Kernels, & Recoveries
Common users of phones, tablets and other smart devices running the Android operating system may have heard of rooting,which is often compared to jailbreaking on Apple devices. Find out all you need to know (all the basics, anyway) about advanced Android customizations, like custom ROMs and recoveries, starting with rooting and unlocking a phone.
What Is Root?
Rooting is the act of unlocking root permissions on a device, and essentially it means allowing deeper hardware and software capabilities. Android originates from the Linux kernel, and so it shares some similarities — root is one of them. Essentially, root users, also known as superusers or admins, have the highest permissions, including the ability to access the root of the file system.
This means root users can install applications with special functions, which can’t be performed with the default permissions in Android devices. They can install apps to block advertisements, completely back up the phone, access the Tor network, enable certain gamepads, and more. That’s just the top of the barrel of the capabilities of root apps.
Essentially, rooting a phone is unlocking its full capabilities. It opens the gateway to other, deeper forms of customization, including installing custom ROMs.
What’s Unlocking?
In the context of Android customization, unlocking refers to the act of unlocking a device’s bootloader. This is what loads when turning on or booting a device. Most bootloaders prevent the installation of custom software like ROMs or kernels, and in some cases, unlocking the phone is necessary before rooting it, as opposed to the other way around.
Unlocking a device’s bootloader can be a little bit harder than rooting it. Most phone manufacturers don’t want users rooting their devices to begin with; and phone carriers especially don’t want that, because it opens up the possibility of switching carriers — the bootloader is usually what keeps users tied to a network and unable to switch to another.
Unlocking the bootloader is key to installing custom ROMs, kernels and recoveries. As a bonus, it unlocks the phone for usage with other carriers.
What’s a Custom ROM?
A custom ROM is a specialized version of Android, developed by enthusiasts to open up the full capabilities of a device or optimize it toward certain purposes. There’s custom ROMs for just about every Android device out there, and thriving developer communities all around the Web devoted to Android development, like XDA Developers.
ROMs typically offer advanced features not found in normal Android, such as more advanced controls in the operating system, special UIs (user interfaces), custom themes, and other features usually not possible in Android, with or without root access. There are many developers, devices and distributions to choose from, so look around the web for information on ROMs that might catch your eye. Before you start, check our collection of custom ROMs.
And a Kernel?
In computing, a kernel controls how hardware interacts with software. This is no different in Android: Just as custom ROMs come around to replace the operating system, custom kernels come around to replace the stock Android kernels found in a phone.
Replacing a kernel with a custom one has a variety of benefits, but like custom ROMs, those benefits depend on what kernel is installed. Some kernels prioritize higher battery life, for instance, while others prioritize performance or add additional hardware features, like sliding the bottom of the screen to lock the phone or tapping it to wake it. Kernels deal more with the hardware side than the software, but can breathe new life into a device, especially one that’s having trouble with battery life or performance.
What About Recoveries?
An Android phone already has a recovery, which, as the name implies, is typically used to recover data in case of the phone being damaged in some way. Recovery modes typically allow performing system maintenance, but custom recoveries add a bit more than basic recovery and maintenance functions.
For instance, custom recoveries are often what we use to install custom ROMs and kernels in the first place. Custom recoveries can also be used for more advanced maintenance functions, and typically enable features like touch navigation as opposed to the hardware-buttons-only restriction of the stock Android recovery.
Is That All?
For a beginner? Just about. You now know everything you need to get started bringing your phone to the next level of customization. I can’t provide exact instructions here, as instructions vary between devices, but I can tell you how to start the search to unlock the true potential of your Android device.
- Identify the model name of your device, as well as information like OS or kernel version. You can find these things in “About phone” in your device’s Settings menu.
- Once you know the exact device you’re using, go to a site like the XDA Forums. There, type in your device name and find the subforum for your particular Android device.
- Once there, you should find a guide for unlocking/rooting your device, as well as topics where developers show off the ROMs, kernels and recoveries they’re working on.
- You’ll find all the instructions for your particular device online, but if you want easy access to the best custom ROMs, check out our collection.
