[Galaxy S 4 Q&A, Help & Troubleshooting] djshotty:
Okay! I've been on this board for almost seven years, with phones ranging from a HTC TouchPro through to my current Samsung Galaxy S4 International GT-i9505. The ROM I'm on right now is (with thanks to AntaresOne) cm-12-20150315-OPTIMIZED-jflte, available from his thread, below...

http://xdaforums.com/galaxy-s4/i9505-orig-develop/rom-cyanogenmod-12-t2943934

Everything works well - it's fast, has great battery life, the images, screen, text, video all look great, the sound for a phone call is clear and loud, ringtones are loud, the Bluetooth works with my Fusion car stereo and I can play video from it to my Samsung LED TV via wi-fi.

The intention of this Helper Thread is to have somewhere just for Australian users with Galaxy i9505's or i9505T's (the Telstra model) ONLY. That way, the discussions and advice shared is much more 'region-specific'.

On that note, I'll share my experiences with how to get the best out of your phone. Firstly, may I just say please read through these instructions carefully before coming to me with questions. I have spent the best part of five years tinkering with an i9000, then a i9100T, now a i9505 International. Also, there's heaps more help and advice to be found here on XDA-Developers, sammobile and a number of other Android forums, so I've always found it best to research as much as possible to take the very best information that actually works. No question is too stupid, unless you ask one that's been answered a thousand times already, like...

What's the best ROM?, What's the best modem?, How do I root my phone?, and Will rooting void my warranty?

And so, we start afresh with a Galaxy i9505, also known as jfltexx. Back up all your photos and music to your PC, and you'll find any number of apps on Play Store to backup your text messages and call logs. Titanium Pro is the best. It does need root access, but fortunately there are a couple ('SMS Backup & Restore' is one) that you don't need root to use. Seeming though 99.99% of everything you can do to upgrade your phone is best off being done with a clean slate, trust me when I tell you - BACK YOUR STUFF UP AND FACTORY RESET THE DAMN THING!

The most important step - BACKUP YOUR DEVICE'S EFS FOLDER!!! This is a location where information pertaining to your device's IMEI number and Country Code etc. are stored, and this folder can sometimes be wiped when you flash a new ROM. From Lollipop onwards, the way that's done is a bit different, but again there's plenty of apps and methods out there that will do this backup for you. Thing is, most often you'll need to be rooted, so...

You'll find throughout XDA a number of device-specific threads and posts about how to gain root access on your device. The fastest and easiest way to perform this task is to go visit Chainfire...

http://xdaforums.com/showthread.php?t=2219803

The specific file you are looking for is called CF-Auto-Root-jflte-jfltexx-gti9505.zip. You use a nice little program called Odin - which just happens to be included in the package you've just grabbed - to 'flash' that into your phone. Yes yes yes, this voids your warranty and trips the Knox flag. Sadly, as much as you might find people who say that it can be reset, KNOX CANNOT BE CHANGED BACK ONCE IT'S 0x1!

Next, go and check out flatzki's thread at...

http://xdaforums.com/galaxy-s4/general/i9505xxuhoa7-odin-files-100-t3043983

He's just got his hands on the Android 5.0.1 Lollipop Stock ROM for the International Galaxy S4 LTE, jfltexx. Thank him while you're there, and grab the ZIP file I9505XXUHOA7_OXAHOA7.zip. Create a New folder on your Desktop, then (using WinRAR or 7ZIP) extract the contents of the ZIP you downloaded into that folder.

Once you've done that, you'll be looking for a way to get rid of the 'dreaded' Yellow Triangle. Go check out...

chainfire's TriangleAway Thread

and follow the instructions from the Master himself. Grab the TriangleAway-v3.26.apk from the link at the bottom of that post, and throw the man a Donation - the guy reigns supreme with these devices and deserves every bit of credit for the support he gives us all.

Next, go and find yourself a ROM. AOSP (Android Open Source Project) ones are the best. The origins of AOSP ROMs are Google's original Android source code, so you're getting the base code of the OS exactly as the Original Programmer intended. Samsung (and other OEM's) then get their grubby little hands on that code, then go to town making it control their hardware in the manner they want.

Now, there's two lists of Custom ROMs for the i9505 that are shared here on XDA:

For tweaked and altered versions of original stock AOSP ROMs, visit the Galaxy S4 i9505 Android Development section.

For custom ROMs that are pretty much 'outside the box', and built from scratch by individual developers or groups using Android source code, visit the Galaxy S 4 i9505 Original Android Development section.

No matter what you decide to 'flash' in, if you have questions about the ROM itself, how to flash it, or anything else about that particular release, ask them of the ROM Chef in the thread where you got it from. They're the ones who cooked it, so they've already gone through the trials and errors and successes of getting their ROM working on an i9505, making them the best guys and gals to ask if you have dramas with the ROM. 99.9% of the time the ROM Chef's thread will have in the first couple of posts Instructions on How To Flash, FAQ's, known issues, etc.

The advice I give everyone regardless of what device you have is, Back the damn thing up first - it's called a nandroid backup, Google it - and make sure you clean all traces of the old firmware out of your phone thoroughly. More often than not, the dramas people have when they get up and running on a newly flashed ROM (or, issues in restarting the device after a flash) can be directly attributed to remnants of the old ROM interfering with the new. This is especially so for flashing via Recovery. If you use Odin to flash a Stock firmware, it pretty much smashes its way over the top of whatever you've got installed, and gives you a fresh palate to work with.

Now, if you're having issues with carrier network connectivity, call quality, mobile internet etc., it could be either your network APN (Access Point Name) settings or your ROM's 'modem' package. APN settings are within the phone's Network setup menu. The best list of Australian carrier APN's I've found is at Ausdroid Forums. Modems are a sort of 'try them until you get one you're happy with' kind of thing, and if you're still in the dark, go and read Formhault's post about the subject at...

http://xdaforums.com/showpost.php?p=50787570&postcount=2549

My advice when it comes to modems is, grab a couple of CWM-flashable modems and take at least two days of testing each until you get one that gives you enwhitenment.

Hope that gets your device running smikko, and if you're that stuck you need a bit of special attention, PM me. Lastly, make sure to click on the Thanks button if you got help from this tutorial...