I'm bone stock, no root and have recently applied the L720VPUFNAE update. Since taking the update, the phone has had nothing but problems. When awakening 50% of the time I will get nothing but a black screen and will have to hard boot the phone. The other 50% of the time, it's extremely slow to accept my unlock code. Half of my home screen shortcuts are gone, just disappeared. Battery life is terrible, just a few hours of life. I've browsed here for solutions and have seen some people having similar issues on other sites, but no solutions. Is there a way to force the update again to see if that fixes it? Any other solutions aside from factory reset? Often times the phone will ring and I cannot even answer it because it won't wake up properly!
So I had the same problem and this drove me crazy. I tried wiping Cache from OS, from Home key+Up volume+power, I tried a factory reset, I event tried applying the 4.4.2 patch via ODIN. I tried removing the lock screen and company email. The problem kept coming back.
Today however I brainstormed with a coworker who also has a working 4.4.2 S4 on ATT. After comparing settings for the lock screen we noticed the new swipe option and turned that on. What a bad move... that locked the phone up hard to the point I kept getting "com.android.systemui" stopped responding. I had no choice but to pull the battery and reset a few times and it didn't fix the problem. At last I had the idea to pull the SD card and boot the phone. That worked!
Everything worked exactly as snappy as it did with 4.3, so I rebooted a few times, got some texts, turned on the lock screen in order of swipe, and then PIN. With everything working I turned off the lock screen and put the SD card back in.
No problems....
rebooted
No problems...
turned back on the lock screen and all has been running well.
I'll report back if it slows down in a few days but at this point I've come to the conclusion that this problem has to do with the SD card. My thought is the Symbolic link which guides the OS to the SD card stay in the system even after the reset or upon reapplying a Play app. The removal and boot without the card removed the symbolic link and reset all the ExStorage to the new Kernel/OS version.
Hope this helps anyone suffering the same problems!!