For those of you using TWRP on your Galaxy S4, please MAKE SURE to update your TWRP recovery to the latest version 2.6 as previous versions do have bugs where custom ROMs may not install correctly.
Older TWRP worked fine but on certain custom ROMs, it would freeze during installation or the custom ROM would not boot causing bootloops. I found out this is fixed by either using CWM or installing the latest TWRP 2.6.
You can easily update your TWRP by using Goo Manager app OR you can also flash TWRP manually using ODIN and TWRP tar files here. Some Galaxy S4 models may not be supported by Goo Manager so use ODIN and TWRP tar files if that is the case for you.
What is a Custom ROM?
A custom ROM is a custom, modified operating system that you can install on your Android device. Basically it's like installing Windows OS on a Macbook. By installing a custom ROM, you can bypass stock factory settings like locked hotspot tether, install new Android versions early, or even convert your phone into another OS.
With a custom ROM, you can really maximize the capabilities of your smartphone by adding custom features that have been developed by open source developers.
How to Install Custom ROMs
First, you will need to root your device, if it is not rooted yet, follow our root tutorial and root your phone.
Once rooted, you should have TWRP installed on your phone. Installation of a custom ROM is easy if you learn the basic of it. If you don't know how to install custom ROMs using TWRP recovery, see our tutorial on How to Install Custom ROM using TWRP!