I tried this and it worked! When I went back to TouchWiz I still had the icon at the top that shows LTE/WiFI download.
I use nova launcher.
1. Go to home screen.
2. Hold down your finger on the screen till menu pops up.
3. Click on Shortcuts.
4. Click on Activities.
5. Scroll down to "Settings"
6. Scroll through the list till you find Download Booster. Click on it.
7. Now you will have a shortcut on your home screen that will take you to the download booster settings screen.
8. Enable download booster.