What is a custom ROM, how to install it and how to remove it

Although there have been some initiatives by some manufacturers, the normal thing is that an Android mobile receives updates for two years. Afterwards, he is more or less left to his own devices. When the system becomes somewhat outdated, there is always the opportunity to give it a new life with a ROM.

However, What is a custom ROM? We will see here how they differ from the system that already comes on the mobile, what advantages they have, the usual process that you must carry out to install them and, if you regret it, how you can uninstall it to leave the mobile as it was.

What is a custom ROM

The definition of custom ROM is more or less implicit in its name. While ROM stands for Read Only Memory, in this context refers to the system that is installed in the mobile. A custom ROM is neither more nor less than that, but personalized. It is the system software that is not the one that came with the mobile, but has been modified or created from scratch by the user community.

In plain words, a Custom ROM is a mobile operating system other than the official one, sometimes modified on the official firmware or based on AOSP, the open source version of Android.

For example, a Samsung mobile comes with One UI, with its peculiarities for better or for worse. The user community may have created different ROMs that bring a stock experience (without Samsung stuff) to the mobile, that dispenses with all Google services and applications, that includes only open source applications or that introduces new features of Samsung models more recent that have not reached that mobile. The possibilities are almost unlimited.

Considering that mobiles rarely receive more than two Android updates, ROMs come to the rescue to bring new versions of Android to mobiles that are no longer updated. For example, LineageOS 17.1 brought Android 10 to the Nexus 7 of 2013. This is one of the big ROM advantages, although not the only one:

• Update the mobile unofficially: When the manufacturer does not provide more Android updates, there may be a ROM that includes a newer version of Android.

• News of similar mobiles: A common resource for ROMs is to copy and paste things from other terminals. It is common, for example, for a ROM to carry news from a recent mobile to similar mobiles of the same brand that were launched before and have not been updated.

• Goodbye, bloatware: Still today some mobiles include too many pre-installed applications and services. Some ROMs focus on eliminating all the extra, resulting in a more agile mobile.

• Stock experience: Especially popular on mobiles with somewhat recharged layers, stock ROMs bring you an experience similar to Android One for these types of mobiles.

• More options: Some ROMs don’t give you less, but more. More customization options and more advanced features that were not in the original firmware.

• More privacy: Some ROMs focus on eradicating all traces of Google in the system or incorporating greater privacy and security protections as standard. There are also those focused on being totally open source.

Of course, not all are advantages and problems can also occur, so it is never recommended to start flashing uncontrollably unless you have experience. The ROMs arrive without any guarantee, so you will have to solve any problem that happens to your mobile in the process yourself.

• Risk of bricking. The risk that something goes wrong during the process and the mobile loops or becomes unusable is always there. Recovering them is possible in many cases, but it will require patience and trial and error.

• Known bugs. Some ROMs are more stable than others, but a number of known bugs are frequently cited and should be checked before installing. These errors can range from the camera not working to the Bluetooth not working and anything else in between.

• Poor camera performance. The Achilles’ heel of ROMs is often the camera app, which is usually not as well optimized to get the most out of it as the original app (unless it’s kept in ROM)

• You need to reinstall from scratch. Except for a miracle, installing a ROM implies starting from scratch, so you will lose all the applications and data on your mobile. If you later regret it, you will lose them again by switching to another ROM or going back to the stock experience.

• Bracket may disappear. This is not usually a big problem with large projects like LineageOS, but other ROMs created more “in house” by enthusiastic developers may stop receiving updates – and fixes – as soon as their creator no longer has time for it or sees that the ROM does not there is a lot of interest in your work.

How to install a ROM in an Android mobile

Installing a ROM is not as easy as installing an application on the mobile, since Android mobiles include certain protections to make it a little more difficult or, in some cases, impossible. There is no universal way to install a ROM on an Android mobile, so it is very important read the instructions carefully project installation.

That being said, there is a series of common steps that serve as a guide on what may be necessary when installing a ROM on an Android mobile. Remember that the final word depends on the instructions of the ROM and the specific mobile:

• First, the root. In many cases, you need root access. It is said fast, but root A mobile is a world, and you will have to find out how to do it on your specific mobile. Usually, it won’t take you long to find it on the XDA forums.

• Unlock the bootloader. The bootloader is the first thing that is loaded on the mobile and in some mobiles it is blocked so that the user does not put their hands in the system. If you have the bootloader unlocked, you don’t need to do anything, but otherwise you probably need to unlock it. Again, the process varies, as some manufacturers allow you to do it easily, while others do not.

• Install a recovery mode. Recovery Mode is a kind of emergency menu in which you can make and undo adjustments to the system, before the system loads. Android brings its own, but it is quite limited. To install a ROM the normal thing is to resort to TWRP, CWM Recovery and the like.

• Download a ROM and copy it to your mobile. Then you have to download the file or files from the ROM itself and save it in a folder on your mobile, unzipped.

• Install ROM from recovery mode. As long as you do not care about the data on your mobile -because it is possible that it will be erased- the next step is to use the recovery mode that you installed before to execute the installation of the ROM. This will generally first erase the entire system (and perhaps data) partition, and then replace it with the new one. Read and follow the official instructions carefully.

• Restart the mobile. The last step is to restart the mobile and wait for it to boot. The first reboot takes longer, so don’t be nervous if it never seems to finish. If everything went well, you will have your new experience soon.

Where to find a ROM for your mobile

CarbonRom

In Android ROMs there is a lot of remix culture, so that many are rehashed from others or that they borrow this and that from other projects. However, there are some great projects whose ROMs end up being ported to a good number of devices. These are the most renowned ROMs:

• LineageOS. First it was called CyanogenMod, then it was reborn as LineageOS and now it has come back strong, updating frequently and with a list of compatible mobiles that does not stop growing.

• Paranoid Android. After a period of silence, Paranoid Android has been reactivated with a version based on Android Pie available for a handful of mobiles and followed by the version of Android 10. You can see the list of compatible mobiles here, although many of them remain with old versions.

• SlimRoms. It hasn’t been updated for a few years now, but it can still be a good option for older terminals. This ROM is based on AOSP and focuses on lightness. On their website you have the compatible models.

• Resurrection Remix. Resurrection Remix is ​​one of the oldest ROMs and basically tries to pack as many features as possible. Here you will find the downloads and compatible models.

• AOSP Extended. It’s like AOSP (Android from source code unmodified), but better, with new features and more customization options. On their website you have the download links and compatible models.

• CarbonROM. Still very active, with weekly builds, it is one of the most stable ROMs out there, with a ton of customization options. You can check the compatible models here.

• OmniROM. Another very popular ROM with versions for a large number of devices, OmniROM is still running, with the Android 11-based version already ready. You can see the list of compatible mobiles on their website.

The ROM web page is a good starting point, although considering that the process of installing a ROM has several moving parts, it is best to use the XDA forums to find the links and download instructions specific to your mobile. Each device has a specific forum dedicated to development, where the different available ROMs and their installation instructions are published.

This is important because sometimes the ROM for your mobile is not an official build, but it has been modified by a third person, so it could have special requirements in its installation or problems that are not in the official version.

How to remove a custom ROM

Have you tried installing a custom ROM and you didn’t like it? Then you can always go back to the official version, although this can be more or less complicated, depending on how much you have changed on your mobile. For example, if you installed a different kernel, you may need to revert to the official kernel before installing the stock firmware again.

Unfortunately, the process is not unique, but depends again on each mobile. Some mobiles have support software, as is the case with Smart Switch on Samsung or HiSuite from Huawei, which can help you download and install the latest official firmware without too much complication. In other cases, you will have to retrace your steps to leave everything as it was.

Again, XDA forums They will help you find the easiest way to get back to the firmware of the mobile. It is a basic topic that will undoubtedly be covered in the device’s forum, and that will often involve downloading the firmware and flashing it, either by connecting the mobile to a PC or from the recovery mode.