Hey I'm in the same boat.
I'm on Baseband version i545vrufnc5 .
I'm new to this and trying to figure out how it all works, but does that mean every verizon samsung galaxy s4 that's running kit kat 4.4.2 is on i545vrufnc5 ?
I'm rooted, but when I try to install a recovery program I get the message "System Software not authorized by verizon wireless is installed" upon rebooting into recovery mode.
From what I've read I can use Odin to install an older kernel, prior to the Knox app and locked bootloader. Then I can install recovery program and the latest cyanogenmod.
Can anyone confirm this? Hate to have a bricked phone.