Frija! Use CSC code USC on auto mode, boom. Now it's US cellular, which did not like my Verizon sim card at all, so here's a really short summary and links to much better help to do all this (knowing all risks and pitfalls etc.) and end up rooted and your Verizon sim still functioning.
Few things, one this was written up with a Verizon s5e in mind, I don't know if the PITs are different for the other carriers, so this one operates with Verizon's in mind. Two, you MUST have a
patched Odin. Also standard advice of backing up everything before hand, and finally, I was dumb and had my SIM card in during the whole process. I'm not sure it had any ill effect but if you want to be super safe, go ahead and keep it out until you're on T727U firmware.
Pre-note: I have no clue if you can substitute t727v for t727u in the following write up. I wanted all traces of Verizon out of my tablet when I was figuring how to enable the Bootloader unlock. We're using the R4 BL files for the whole process so it may or may not effect anything as far as that goes.
1. Do a standard flash of the R4 official Samsung firmware. (You might have to use the us cellular pit for this flash. If so remember to use either the U or V pit for step 3.)
2. Follow
AHE_XDA's fantastic guide, right now only the parts about unlocking the bootloader.
3.Once that's done, flash The AP of T727U firmware, with the cp and csc ofT727V
Note: Not the BL. We do not flash anything to the BL after the R4 firmware in step 1.
Addendum: Use the Verizon pit (usa_open) when flashing to t727U the first time if you get a "could not open file on line ****" error from odin.
4: Follow the rest of AHE_XDA's guide on rooting and there you go!