I had similar issues. The way i solved it was to power off and pull out my external sd card, I then booted into recovery and formatted all partitions (including the internal sdcard) except for /modem and /boot. I then used the recovery option to reboot into download mode so I could Odin back to 4.1.2 (VRAMC3). Note: It will ask you if you want it to repair root when you go to reboot, I chose not to.Oh! Yes I did, just forgot to mention those steps lol. Thanks for the quick response though!
Once in Odin with the phone showing connected I loaded up KIES_HOME_I605VRAMC3_I605VZWAMC3_1098177_REV04_user_low_ship.tar.md5 into the PDA slot and also loaded sch-i605-16gb.pit into the PIT slot. Loading the pit file should enable the Re-Partition checkbox. Should look like this:
With Auto Reboot, Re-Partition and F. Reset Time all (and only those) checked, I clicked start, waited, and everything was successful. The next step was to get back into download mode and Odin flash the 4.3 firmware located here: https://www.androidfilehost.com/?fid=23269279319198557 also using the PDA slot.
I then proceeded with unlock/root using CASUAL 515b and the steps listed in this thread: http://forum.xda-developers.com/showthread.php?t=2272066
After that everything went perfectly with getting 4.4.2 up and running.
Oh one more thing I had to do was install FolderMount and run it once to repair something that was not letting 3rd party apps write to the internal sdcard. I removed it after it applied the fix but it looks like it could come in handy in some situations.
This may be a whacky way of doing things and there are definitely no guarantees, but it's what worked for me.