[AT&T Samsung Galaxy S 4 General] Rastabolino:
This guide is intended to be an all-in-one resource for people coming to Samsung phones after using other devices. It is a general introduction to the S4 and a glossary/explanation of terms you may see here in the forums.

This thread is slightly out of date but the info is still good, I will be updating again soon!!! Remember to hit thanks if this was useful :)

Disclaimer "Just because I am trying to be helpful does not make me responsible for anything that you do to your phone. Playing with any of this stuff could destroy your phone"

The layout of this post is as follows:

Welcome

FAQ

Glossary of terms

First off, welcome to XDA

The XDA community is home to the most talented and helpful phone developers on the planet.

These developers spend lots of their free time working on making all of our phones better. You should be nice and respectful to them and follow the rules. WHY? If the statement above isn’t enough reason then think selfishly, the less time they are dealing with redundant questions, the more time they have to develop stuff for all of us!

Help them help you by following the following basic rules:

1.If you are confused or have a question, the first thing to do is READ! Read lots, look things up both on xda and using google.

2.If after searching you still have not answered your question, then post in the Q&A forum.

3.Asking for ETAs on ROMs, updates, etc. is considered rude.. DON’T DO IT!

4.Don’t report bugs to a developer unless:

a.You know 100% that it hasn’t already been reported,

b.You know how to reproduce it

c.You can get a logcat of the problem (more on this later)

Some advice if you are new to all this and don’t want to ruin your phone:

1.Be patient. Don’t be the first or even the tenth person to flash anything. Wait until you see others using whatever Rom or kernel with success.

2.If you have any doubts about what you are doing, read more. Don’t flash.

3.Make sure you are in the forum for your device, not some similar or related device.

FAQ:

Q. Is my bootloader locked?

A. Only if you have an AT&T or Verizon phone

******* Info for AT&T users *******

Q. What is LOKI?

A. Loki is an exploit for phones with locked boot loader that allows us to bypass the locked boot loader in order to install custom roms or recoveries. More Loki info down below

Q. Whats the deal with MF3?

A. MF3 is the current firmware from AT&T that comes on any new phone. Your phone may also auto update to MF3 if you are not careful. MF3 patched the ability to use Loki to install custom roms/recoveries so if you are on MF3 things are much more difficult.

Q. How can I keep my phone from updating to MF3?

A. If you want to avoid the update, you should root your phone and freeze the following three apps using titanium backup or some similar app.

1. AT&T Software update Vxx_x_xxxx_x_x

2. FWUpgrade x.x.x

3. LocalFOTA vx_xxxx_x_x
​

Why flash?

by flashing your device you can make your phone act differently, look different, and enable new or disabled options. you could ,for example:

enable native tethering

enable call recording

change the look of your phone

add custom toggle buttons

overclock or undervolt

increase battery life

etc..

Kernel vs Rom vs Recovery vs Modem

Kernel is the layer between the phone hardware and the rom. it controls things like Wi-Fi power, touch sensitivity, possible range of screen brightness, phone logging, and processor max and min speed. kernel must be designed not only for your device but also for the type of rom you are using (Sammy rom or Aosp) some kernels support all roms, others are specific.

Rom is the operating system of your phone. there are three main categories of roms.

roms that are based off of the Samsung stock rom (Sammy rom)

roms that are based off of Android open source project aka AOSP (AOSP, AOKP)

roms based off of the miui project (these used to be a branch of AOSP but recently they have also used Sammy base for miui)

recovery is a partition that you can access at boot by holding down a combination of keys. (volume up and home button in the case of our sgs4) every phone has recovery stock but it doesn't do much. you can replace stock with clockwork mod recovery which is extremely useful for flashing all kinds of things and making backups before you do. There are other alternative recoveries besides clockwork but that seems to be the most common. TWRP is also gaining popularity these days. You can easily switch between recoveries and or upgrade your current recovery. All that needs to happen is for a new image to be flashed onto the recovery partition. See the rooting guide for more info on how to flash a custom recovery.

modem is a file that controls the cell radio of the phone. Helps determine what frequencies to use and settings for a particular network. It is important when flashing a radio that you flash a radio that is for the AT&T sgs4

Methods for flashing files - Odin vs mobile Odin vs. clockworkmod(cwm) vs adb

Odin is the internal Samsung tool for flashing. I believe it only exists on Windows platform. This tool is mostly used to initially flash an insecure kernel or rooted kernel, OR to return to completely stock rom.. Files for flashing in odin generally should end in .tar or .tar.md5 although sometimes they come zipped and the tar is inside the zip. Read more about Odin before using it as it can easily break your phone. !!!as a general rule make sure you never check the "partition" checkbox EVER!!!

Mobile Odin (THIS TOOL DOES NOT SUPPORT ALL S4 MODELS...make sure you check that it specifically works with yours first. I think at this time it works on your phone unless you have locked bootloader but STILL DOUBLE CHECK) is a phone based version of Odin made by the very talented developer Chainfire. It can be installed on a rooted phone and used to flash the same .tar based files as the desktop version. Mobile odin has a few advantages. 1 you can use it from your phone. 2 it can auto root a stock rom (nice if you want to try out a brand new update that has not been rooted yet)

clockworkmod(cwm) or TWRP is recovery based tool that can make backups of your entire phone, flash new roms, kernels etc.., and do many other useful tasks. Once you have this on your phone my guess is that most of your flashing will be done through this tool. The files for flashing through clockworkmod are .zip files.

ADB is the android develpment bridge. It allows for command line interface with your phone through its debugging options. ADB can do most anything as I understand it. In my several years of flashing I have only had to use it once, and i could have waited for someone to come up with another solution. In general as a noob i recommend you stay away from ADB.

open source vs Samsung base(aka Touchwiz or TW) vs miui

Open Source Roms such as AOSP/AOKP are built using Google's open source android code as a base. The developers then add functionality specific to the device. The advantages of these builds are that they often have tons of options built in to the rom that change the behavior and look of the phone. They usually allow you to change the toggles in your notification pull down, change the battery display, make all kinds of adjustments to sounds, vibration etc... Some people also prefer the "vanilla" android look and feel. These roms often provide "bleeding edge" concepts, design, and modifications. The Disadvantages of these roms is that some of the hardware coding is done closed source by the phone manufacturers, which means that things like Infrared, bluetooth, camera, video recording, and MHL video out often don't work or take much longer to get working by the developers. Basically anything that relies on the Samsung framework will not work in an open source build. This means Svoice, Snote, and the Samsung camera app will not work.

Samsung based roms (aka Touchwiz/TW) are taken from the Samsung original phone software and modified by the developer. Usually, these roms are modified in order to be faster and to make changes to some of the features. Expect to see changes to the stock rom like: debloated (ATT and samsung software removed), de-odexed (explained later), enable tethering, unlimited sms recipients, added notification toggles, etc. Most of these changes are made to: make the phone faster, improve battery life, make the phone easier to theme. The advantage of these roms is that they still use the Samsung framework so all the proprietary stuff like camera, bluetooth, MHL still work, the disadvantage is that they will never be as customisable as open source roms.

MIUI is a rom that focuses on theming. Official MIUI (Chinese) gets updated weekly on Friday and then there are lots of miui developers who adapt it to other languanges and make some tweaks to it. MIUI can be built from AOSP source or Samsung source and depending will have different features. The first MIUI rom for our phone just appeared in these forums and it is based off of AOSP. MIUI has a unique look and is also highly customizable through theming. There are tons of themes available for download through the rom itself and you can mix and match any part of any theme you want. This includes icons, lockscreen style, etc.. Some people criticize while others praise MIUI for being very "iphone like". This is because the icons look more iphone like and there is no app drawer in the MIUI launcher. However, you can still use any launcher you like within MIUI.

odexed vs de-odexed

odexed is how the phone comes stock from Samsung. Odexed means that system files and apps are split into two pieces and kept in different places on the phone. This is done to speed things up a bit. However, it makes it harder to theme the phone because the apps are split up. Most custom roms choose to de-odex (basically regroup the files back into one) so that custom themers can make themes more easily for the phone.

Flashing "dirty" vs flashing "clean"

Clean

Doing a clean install of a rom means erasing or formatting all the data from the previous rom before you flash the new one. This is the prefered way to flash a rom to ensure that it will run smoothly. It is necessary if you are switching from one rom type to another (CM to Samsung base). In order to do a clean flash you need to boot into recovery and select the following options: wipe user data (this wipes all apps and personal data, but not your photos/videos), wipe cache, advanced>wipe dalvik cache, storage/mounts>format system. This will ensure that no trace of the former rom is left on the phone. Beware that at this point your phone will not boot until you install a new rom. I suggest using titanium backup to backup apps and smsbackup+ for texts to make getting your new rom configured easy.

Dirty

Doing a dirty install means just flashing a new rom right over the top of the old one without wiping any data. The advantage to this is that you don't lose any apps or account info. The disadvantage is that you open up the possibility for problems. Generally you only want to flash this way if you are upgrading a rom (CM10 nightly to the next nightly, or from one samsung based rom to another). If you decide to flash over the top and have any issues, you should not report bugs, but try flashing clean first.

Logcat

Logcat is a way to access the android system log for everything that is going on behind the scenes. This tool is used to help developers pinpoint problems in a rom. If you want to actually be helpful to a dev when reporting a bug, you should really learn to use this tool. I am no expert on logcat but you can find some good information in this post: http://xdaforums.com/show....php?t=1726238

What is the Bootloader?

The bootloader is basically what it sounds like...it loads the boot image of the device. Basically it is one of the first things to run on the phone and it shows the phone where to find the boot image and how to start. The bootloader is also responsible for allowing access to the recovery part of the phone.

Locked Bootloader?

This seems to confuse a lot of users so here goes: The AT&T and Verizon versions of our phone have a locked bootloader. What does this mean? To the noob, it means that the devs had to figure out how to bypass or unlock this part of the phone in order to be able to boot custom recoveries such as CWM and TWRP. Getting a custom recovery means being able to backup the phone as well as flash custom roms. Luckily for us, Djrbliss (make sure and thank him! his thread is here:http://xdaforums.com/showthread.php?t=2292157) figured out how to bypass the locked bootloader. The exploit he used is known as Loki. Please remember that the loki exploit is not the same thing as unlocking the bootloader, it is a bypass/trick. AT&T and Verizon have fixed the exploit that allowed loki to work in there newest firmware. Loki patch will not work for MF3 firmware or later.

Loki

refers to the exploit that allows us to run custom recoveries as well as custom roms. You only need to have a loki'd rom if you have a model with a locked bootloader (AT&T). Thankfully, you can install a custom recovery that will auto-Loki any rom you flash so that you can install almost any rom built for our model phone (see below). I strongly recommend flashing an auto loki recovery if you have a phone with locked bootloader. I use this one here: http://xdaforums.com/showthread.php?t=2291956

Compatible Roms

you should be able to run any rom built for AT&T, TMobile, or the I9505 international model (NOT I9500!!) as long as you flash with an auto loki recovery. You can check out this thread for more info. Make sure and thank TheAxman! http://xdaforums.com/showthread.php?t=2295557

You may have to manually set the APN. If you encounter problems with the rom look in that roms thread for answers.