Custom ROMs are very popular for Android devices. Every Android smartphone has its own custom ROM created by developers who have that device. Custom ROMs have come a long way since the beginning of Android. Back then, these ROMs were used to make devices faster, smoother and lag free because Android was very slow and buggy.
But now Android is considered as one of the most stable operating systems. Android is now fast, smooth and completely bug free starting with Ice Cream Sandwich, then Jelly Bean with Project Butter and KitKat which supported devices with only 512 MB RAM.
Nowadays, custom ROMs are used to add more features, options and change the design of the phone software. There are many custom ROMs for one specific device. Popular devices even have more than 10 custom ROMs to enjoy.
The most annoying thing about custom ROMs is that for every update, you have to download and install a huge file. For example, on Samsung Galaxy devices, even if the update is minor, you have to download the entire 1 GB ROM just for those little added features. If you are tired of downloading a ROM update for just a few small features, this is the solution. You can make the ROM update file size smaller than what it is originally.
Now, you can get the current ROM installed on your phone, compare it with the new ROM update file and then a new zip file will be generated containing only the features and updates. This can turn a 1 GB ROM update to a 10 MB zip file.
Also Read: Best Custom ROMs for LG G3 (Fast & Stable)
Once you have gotten the small ROM update zip file, simply flash it through Recovery like you would do with a normal ROM. You get all the features of the new ROM update without having to even download the whole ROM.