Unusual Softbrick?

So, I WAS going to use T-mobile's JUMP! program to get the S6 Edge, so I wanted to revert my S4 back to stock. I found out too late that I can't do that; because of the bootloader, it won't allow me to downgrade back to 4.3/4.4. I tried using Kies and I tried multiple solutions to Kies (including editing a config file, updating Kies, and doing a fresh install of Kies); anyone who's used it knows that it's crap. My window grays out and Kies becomes unresponsive and I end up just closing it.

I also tried using Odin 3.10.6(?), except when I tried, I kept getting failures. (Can someone show me how to add pictures to my post?)

On my phone screen it reads:
ODIN MODE
PRODUCT NAME: SGH-M919
CURRENT BINARY: CUSTOM
SYSTEM STATUS: CUSTUM
KNOX KERNEL LOCK: 0X0
KNOX WARRANTY VOID: 0X1
CSB-CONFIG-LSB: 0X30
WRITE PROTECTION: ENABLE [text in grey]
eMC BURST MODE: enabled [text in grey]
START (224, 1440) [text in red]
SW REV. CHECK FAIL : FUSED : 5 BINARY : 1 [text in red]

I'm assuming for a quick fix, I need to download a custom rom in a .tar form instead of the regular zip and start over from scratch with a custom rom?

EDIT: On Odin 3.10.6, it reads:

<ID:0/003> Added!!
<ID:0/003> Odin engine v(ID 3.1005)..
<ID:0/003> File analysis..
<ID:0/003> SetupConnection..
<ID:0/003> Initialization..
<ID:0/003>Firmware update start..
<ID:0/003> SingleDownload.
<ID:0/003>sbl2.mbn
<ID:0/003>NAND Write Start!!
<ID:0/003>sbl3.mbn
<ID:0/003>rpm.mbn
<ID:0/003>FAIL! (Auth)
<ID:0/003> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)