Question [Q] Can't Read Sim After Odin Flash to 4.4

Hello!

My SM-N900T isn't reading my SIM Card after doing some stuff to my phone, most notably flashing from 4.3 to 4.4. I tried flashing a ROM for the old boot loader (because I'm dumb) and of course got boot loop. I've done this before, I believe, and was able to Odin back to stock and all was fine, so I fired up Odin. I figured I'd pull a 'two birds, one stone' and flash the newest version of the software on the phone while I had it open. When the phone came back up it it just had a crossed out sign where the signal indicator should be in the status bar. I got a SIM Card app over wifi and it didn't see a SIM Card. I tried another card and it didn't see that either. I've tried reflashing with multiple different variables, but to no avail.

tl;dr
Flashed 4.4 ROM on 4.3 Bootloader
Odin'd up to 4.4
Can't see SIM Cards

Any suggestions?