My Experience and FIX
sorry to resurect an older thread, but here's my fix for softbooting XXUGNE5 and others:
On a Galaxy S4 (i9505 variant) I successfully updated with a flash of I9505XXUGNE5 and later I9505XXUGNG8 (4.4.2 Kitkat) through ODIN and rooted both times;
I9505XXUGNE5 was rooted using Towelroot V3;
I9505XXUGNG8 was rooted using the CF-Autoroot method (google for instructions).
In both cases, after a successful root, and successful SuperSu update, the Galaxy S4 (I9505) became unstable, suffering random softboots, usually on system wake.
After some research, I found that the system softboots where fixable, but was disappointed that I did experience 1 softboot post the fix. I therefore set upon completely eradicating the problem causing the crash.
First off; the crash fix was identified by xxxx, who wrote an Xposed Module (SSCF) that could be loaded through Xposed Installer. This module, once installed, could prevent the crash, and log the error causing the crash. In my case, the crash log reported something to do with com.sec.knox.seandroid
Again after some research, it appears that when you first open SuperSU after rooting the device, you are asked if you wish to block KNOX, which I did, and which appeared to have been successful. However, my understanding is that KNOX will still attempt to flash error/warning messages even whilst being blocked by SuperSU, and I suspect that this message/block combination was somehow confusing the system and causing the crash.
On my device, I9505XXUGNE5 was crashing every 10 minutes, and I9505XXUGNG8 less so, but still annoyingly so.
Trawling the threads across the internet, I found a multitude of potential fixes and remedies, and decided to try them all as a combined self-defense attack against the crashing.
14 Steps to a smooth Galaxy S4 (I9505)
1. Backup any data as necessary
2. Boot the device into recovery and wipe data/factory reset
3. Flash your Galaxy S4 (i9505) with a stock firmware (I’d recommend I9505XXUGNG8) using the ODIN method
4. Root the device using the CF-Autoroot method, again through ODIN
5. Boot the device into recovery and wipe data/factory reset
6. Once up and running, either before or after your data restore from backup, download the latest SuperSU by Chainfire from the google play store (worked for me)
7. Open SuperSU and when prompted block KNOX (precautionary step)
8. Download and install Xposed Installer
9. Download and activate the SSCF module by xxxx
a. This module will prevent any crashes and report the cause in the log file
10. Download and install Terminal Emulator from the google play store
11. Open Terminal Emulator and type
a. SU [enter]
b. pm disable com.sec.knox.seandroid [enter]
12. Download and install NoBloatFree from the google play store
13. Run NoBloatFree and disable ALL KNOX related files/apps [I disabled rather than delete, and the system has been stable]
14. Now your Galaxy S4 (I9505) should run smoothly, should not suffer any KNOX related crash, but if it does is set up to auto prevent and log any crashes caused by com.sec.knox.seandroid