[How To] Upgrade Samsung Galaxy S4 firmware via Odin

IMPORTANT
Before you begin with the flashing process, make sure that you:
 - Phone battery is fully charged
 - Back up any data
 - Install Samsung USB drivers (not needed if you've installed Kies)
 - Exit Kies (Make sure you're not running Kies simultaneously with Odin)

DISCLAIMER
You follow this guide and use the software at your own risk.  This method was successfully tested without any issues.

PREREQUISITES:
 - Stock firmware (extract the zip file to a convenient location. It will contain an MD5 file)
 - Odin
 - Galaxy S4 (I9500/I9505)

STEP 1: Put your phone in 'Download Mode'.
 - Turn off your phone completely
 - Hold volume down + home + power button sequentially
 - Press volume up key to continue (Warning screen)*

* It should display a green/ yellow Android logo. In case this doesn't show up, then you should power off the phone again and repeat the action until the Download Mode is entered.

STEP 2: Start Odin
 - Connect your phone to your computer*
 - Do NOT check/tick ANY settings/options on Odin**
 - Click on PDA and select the MD5 file you've extracted
 - Press Start and wait for it to complete***

* A blue box should appear on Odin signalling that your device has been detected [ID:COM]
** The only settings that should be ticked/checked are "Auto Reboot" and "Reset Time". Double check before proceeding.
*** Once started, DO NOT remove the USB cable or turn off your computer until the device has rebooted itself. If the Odin hangs/freezes for any reason before flashing initializes, it is OK to detach your phone from your computer. Once the flashing sequence has completed, Odin will give a ‘Completed’ message in the Message box, and a green PASS will appear on top. Your device will automatically reboot.

DOWNLOAD LINKS:
Samsung USB Drivers: http://forum.xda-developers.com/showthread.php?t=961956
Odin: http://www.putlocker.com/file/C5568DD575E4B760
Samsung Firmware: http://www.samsung-updates.com