Update 5-21-14: I finally updated to 4.3 and had to redo this mod. Just confirming it worked for me.
DISCLAIMER: This was done on a T-Mobile Samsung Galaxy S4. Model # SGH-M919. It may or may not work on other devices. If you have another device and it doesnt work thats probably why. So please be careful. This requires root as well. And please make a Nandroid backup before making changes. Of course please dont blame me if your device goes thermonuclear. It worked for me and it should work for anyone running stock rooted like I am. Again please take the time to do a Nandroid backup first just in case. It takes a little more time, but is worth it just in case you have an issue. So far I haven't had any issues if you name or spell something wrong. Unlike a build prop theres less chance of a brick. OK, so onto the Mods.
Hello all. After reading several threads about asking about the missing data toggle from the notification area I did some research and testing and figured out how to get it back with root and sqlite editor using the stock rom. I remembered a thread about a similar issue with the Verizon S4 and it missing the Wifi toggle. I used the same steps and the sqlite editor from here and was able to add the data toggle back.
Here are the steps I used for the Mobile Data Toggle, read on below for how to add others. (Thanks to The Poetic Vampire)
1) Download sqlite editor app. I got it from here.
2) Open the app and give it root permissions. It should populate a list.
3) Scroll and Tap the "Settings Storage"
4) Tap "Settings.db"
5) Tap "System"
6) Scroll down until you find "notification_panel_active_app_list", tap to highlight it. I noticed its a little hard to get it highlighted because it seems to want to highlight the one under it. So you might have to tap the one right above it to get it highlighted. Make sure its the notification_panel_active_app_list, and NOT the notification_panel_default_active_app_list. I picked the wrong one the first time and it didnt work.
7) Once it is highlighted tap the phones menu button.
8) Tap "Edit Record"
9) You'll see a list of all the toggles that are currently enabled to show in notification area.
10) At the bottom of the list add ; and the words MobileData then another ;. So it will look like this at the end. ;AirplaneMode;MobileData; Then press Save.
11) Reboot and you should have a data toggle now. You can now use the edit feature and move it anywhere you want in the list of toggles.
Note: After I edited it and rebooted the "notification_panel_active_app_list" moved closer to the bottom of the list. So if you go back in and dont see it scroll further down.
OK. Thanks to member "The Poetic Vampire" you can also add several more of the missing toggles. Use the same method as above. Just add the words exactly as below to get SmartPause, Brightness (Thanks Mister Junky), and Wifi Hotspot. You must end the string with ; for this to work.
Brightness; (mentioned by Misterjunky)
UPDATE: Im getting a lot of requests for the flashlight toggle so I decided to add this to the OP so that others with the same question have the answer without having to read the whole thread. As far as I know this isnt possible using this method. In order for it to work it would have to be a toggle that was originally there, but removed. Like T-Mobile removing the Data toggle. Im sure it is possible in a custom rom, but that is way out of my expertise. For flashlight toggle I use Power Toggles in the play store. It works great to set up almost any toggle you want. And highly customizable. Ive added a pic here to show the way I have Power Toggles set up. The lightning bolt shaped toggle is flashlight. Hope this helps.
Uploaded with ImageShack.us