What is a GSI on Android and how is it different from a Custom ROM?



In 2017, with the release of Android Oreo, Google made the biggest change to Android’s underlying foundation since Android’s release in 2008: Project Treble. Not only has this made it easier to roll out updates for OEMs, but we’ve also seen the birth of GSIs, or generic system images, as an alternative to traditional custom firmware.

You’ve probably come across this concept a few times in the context of custom ROMs. The question remains, however: what are GSIs and how are they different from traditional custom ROMs?

What are Generic System Images?

Generally, the way most conventional custom ROMs like LineageOS are made is that they are compiled from source code with a specific device in mind.

This means that the ROM not only includes a system image, but also includes a kernel and all of the device-specific blobs and libraries, as well as other hardware-specific code, needed not only to replace the original firmware of a phone, but also for most components and functions. job.

This has advantages, but also a lot of disadvantages. With custom ROMs specially designed and compiled for a specific phone, a developer or maintainer can take time to fix any device-specific bugs that may arise, such as Wi-Fi or cameras malfunctioning.

But this type of ROM needs a developer – or often a team of developers – to take the time to do the legwork manually and get a custom ROM to work on a new phone. It takes careful reading, testing, and a lot of trial and error. If there is no one there for the task, you may not be able to install a custom ROM on your phone at all.

Related: 12 Reasons To Install Custom Android ROM

2017 saw a big breakthrough in this regard. With Android Oreo, Google announced Project Treble, which essentially modularizes and separates lower-level hardware-specific code from the Android system itself.

The system image essentially acts as a layer that is applied over the lower level code, which means that you can swap out the operating system without needing to touch that lower layer. This gave birth to the concept of GSIs, or generic system images, which can be used on multiple phones.

The main purpose of this change was to address issues related to OEMs’ slowness and inefficiency in deploying Android updates. But it has also been a game-changer for the modding community.

While device-specific custom ROMs were and still are a thing, the developers are also creating custom ROMs in the form of GSI, which you can install on any Android smartphone. The only requirement is that it must have an unlockable bootloader.

Will there be any differences if I use a GSI?

Android recovery mode page options

There might be, or there might not be, it will all depend on your specific device. The problem with device specific ROMs is that a developer would dedicate themselves and pay close attention to that specific device they are managing.

If a problem arises with these types of ROMs, the developer can devote their attention to resolving it properly.

GSIs, however, don’t get the same kind of attention as they’re designed to be used on any Android device. Problems arise often, and to the credit of the developer community, titanic effort is put into fixing device-specific bugs and issues on these GSIs to make them work best on as many phones as possible.

But it’s impossible to fix everything for everyone, and unless your problem happens to several others, it will likely be very low on the developer list.

Related: CopperheadOS: The Secure, Private, Google-Free Android ROM

This doesn’t mean that GSIs are bad. This is the only way many phones can get custom ROMs, and for the most part, they’re just fine for everyday use on the vast majority of smartphones. But if there is a device-specific custom ROM available for your phone, this is probably a better option.

If not, you can try a GSI. Try to check if other people are using the same phone as you are using GSI, and if they are using them, try noting any issues they are having, if any. And if you stumble upon something, be sure to report it.

Custom ROMs for everyone

Device-specific ROMs are always the best option if you want to dive into the world of Android modding. But, if there isn’t, a GSI might be your best bet.

This will allow you to run a different Android experience no matter what phone you have, as long as your phone is compatible with Project Treble. Hope now you know the difference.


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