[Sprint Samsung Galaxy S 4 General] unikron:
***First off I would like to state that there are plenty of similar documents out there but they are usually limited to a specific firmware version of your phone but they dont bother in any way to mention this little fact which in turn causes a lot of headaches. So to make it all simple, I have written this nice guide to help you unbrick you soft-bricked phone or to simply revert back to a factory set phone (just in case you want to unvoid your warrany).

How-To Unbrick and or Factory Reset the S4

You will first need to download the latest software. Find links below:

Odin 3.07 or higher. If the url below is dead just google search and you will find it.

uploaded.net/file/m9edxzk9

You will need to download the proper firmware/OS for your phone. Before you just arbitrarily pick out a version to install, you need to see what version you already have. The S4 is designed so you CANNOT DOWNGRADE. At least not easily so I wont even get into it here. You MUST install either the same or a higher version. But remember that once you install a higher version there is no going back to lower versions. For ex: If your version is L720VPUEMK2, you must either stay with this version or download a newer one such as L720VPUFNAE. Use the link below to find the version you want to install.

samsung-updates.com/device/?id=SPH-L720

**Please keep in mind that the firmware files are quite large and the download mirrors are usually pretty slow. So you may expect an entire day just to download it.

Now that you have downloaded the needed files you are ready to go. Here are the steps below:

Place your S4 into Download Mode. To do this you must power off the device first. Hold down the Volume-Down, Power, and Home buttons simultaneously for several seconds until you see a window alerting you about download mode. Once you are at this screen press Volume-Up to actually place the phone into Download Mode.

Open Odin. Make sure you run this as an administrator. To do this simply right-click the file and select "Run as administrator".

Connect a USB cord from your PC to your device. Odin should automatically see the connected device and you will see COM port being used at this point. Make sure to use a good USB cord for this operation as cheaper cords generally cause the process to fail. The best cord is usually your factory cord that came with the device.

Sometimes Odin defaults these properly but best to be safe. Make sure the "F Reset Time" and "Auto Reboot" checkboxes are checked inside Odin.

Click the PDA button inside Odin and select the extracted MD5 file (the firmware file you downloaded). Make sure you have extracted it from the zip file somewhere before you try to select it here. This may take several seconds or even up to a few minutes to return since its a large file.

You are ready to go. Click the Start button inside Odin and it should start uploading the file to the device. Keep in mind that these files are large so it may take upwards of a half hour to copy it to your device.

Once it is copied up, it will install the image on your device and reboot itself (maybe even reboot 2x automatically). Be patient as it comes up.

That should get you back to the factory setup. However, if your device had been soft-bricked, its possible that you may get stuck at the Sprint boot animation screen like mine did after it reboots. Or perhaps you simply want to wipe the device and start over. Follow these next steps to get it going.

Place the device into Recovery Mode. To do this power the device off. Then hold Volume-Up, Power, and Home simultaneously until the device boots and you see some extremely tiny blue text at the top of the screen indicating that it is booting into Recovery Mode.

Use the volume keys to navigate the menu up and down. Move down to "wipe data/factory reset" and press your power button to select this. It will ask you to confirm so scroll down to the "yes" choice and hit the power button to accept.

Once this process is finished, select the reboot option and hit power. Your device should now reboot and come back up.

Please keep in mind that after performing either a firmware upgrade/reinstall or even a factory reset, your phone may take more time than normal to restart. Once it finishes however, you should be able to do what you need on your device. This method will also restore your warranty counter. Anyhow I hope this helps everyone that has had issues with the S4 and needed a clean slate. The described methods will also work for other carriers as long as you download the proper firmware. But just remember to proceed at your own risk.