Sprint SPH-720T Domestic SIM unlock

[bubbared64]

I have a Sprint Samsung S4 SPH-720T that I want to use on Walmart Family Wireless (T-Mobile). I've rooted it, flashed the modem to work with GSM, but I'm still getting an Invalid SIM error. Sprint has given me the MSL for it. What else do I need to do in order to get this thing to work? It's running 5.0.1 os, the baseband is ending in MK5.

It's not life or death, I plan on using my S7 later on, the S4 is just a temp phone while I port #'s. The S7 according to Sprint is real easy to change carriers. At this point it's more of a want to know kind of thing and have a spare phone in case my S7 bites the big one.

Thanks

 

[Fangthane]

Not sure if you're still looking for a solution, but here's one from XDA. It looks to be a bit more complicated than what you've outlined. I haven't put much effort into doing the unlock, since I've only had the phone for a couple of days. It says you have to be on a 4.4 ROM, but CM11 wouldn't work for me, so I'm assuming it has to be a TouchWiz ROM. I'm not sure if I can just Odin back to 4.4 when my phone came with OK3 baseband/bootloader, so I'm not in a hurry to potentially do something stupid.

http://forum.xda-developers.com/showthread.php?t=2530610