The Heimdall stock flash worked, in that it got the OS reinstalled on the phone. GPS never seemed to work. TowelRoot still works. To get “Wireless Hotspot & Tether” working I installed WanamXposed and if I recall correctly “X Tether” module. Anyhow, this all worked on Bell up north.
There is another version of the stock image called “337UCUFNB1_100%_Stock” which can be rooted also with TowelRoot, this module and some of the Google Play Edition TW /SafeStrap ports of the SGH-I9505 also worked with GPS.
Currently here’s what I’m running / the process:
1) SafeStrap (has to be installed over a stock rooted ROM, ODIN, Hemidall, etc).
2) Advanced wipe everything but the SD card with the installer data on it (ROM, NB1 modem modules, SU Update).
3) Graviton S4 v3.2 for SafeStrap (4.4.2 NB1).
4) [MOD][Script] SmartDebloater [4.3-4.4] (note: don’t remove Samsung Calendar as TW requires it, I also left the camera and calculator)
To get the Google Now Launcher to work correctly as the default (and not TouchWiz Home) I installed Nova Launcher, disabled the Google Now Launcher, set Nova to default, and then re-updated/installed the Google Launcher.
I installed Wanam Xposed, a few modules, and GravityBox. Graviton has a number of tweaks baked in. I tried the “SlimSung NI1 ROM” but the radio seemed screwy since it was built for the NI1 update, the NB1 radio seems okay in Graviton, GPS and wifi seem to work fine.
Quickoffice isn’t available on the Play Store anymore, but this link goes to a Google support page, that launches a “browser only” Play Store whereby you can install the app to your device via the web play store interface. Worked for me anyhow. I’m sure the APK is available somewhere as well. All other apps can be installed via the Play Store.
GravityBox has a tweak whereby you can set the double-click behavior of the home button to launch Google’s Voice Search which is nice. The Google Now Launcher swipes left-to-right from the home screen to get to Google Now. You could also just leave “Google Now Listening” on from all screens.
Another nice GravityBox tweak is changing the number of home screen icons to display, the stock GNL is 4×4 which looks huge on the S4, I think 5×5 or even 6×6 means you might only need a single page.
The one “feature” of TouchWiz which seems impossible to get around is the ability to take photos from the lock screen while using a PIN or password unlock. I’ve tried nearly every conceivable hack, it simply doesn’t work. If you have no security (e.g. swipe unlock) you can take photos, but any sort of PIN or pass means you have to unlock to get to the camera. Oh well. The S4 camera seems pretty decent, definitely an upgrade from the N4. Probably not from the 5S.