G900T Temporary Unlock Question

I got an old G900T from a friend and called T-Mobile to unlock the sim so I can use the phone with another carrier. They called my friend to ask if it was okay and they said yes so they were going to provide me with the unlock code that would be emailed to me. The woman on the phone told me my friend still owed money on it so they could only issue me a temporary 30 day unlock and then after the 30 days it would be locked again until the phone is paid off. Once paid off I would be given a code that would unlock it permanently.

My question is, if I root and flash this phone with a custom rom will that prevent T-Mobile from locking it again after the 30 days? Or will they still be able to lock it after the 30 days has ended?

Kali + G900T + ath9k_htc Drivers

Has anyone successfully compiled a kernel that has these specific drivers implemented into them? I try to compile the kernel myself (The ones directly from samsung themselves for 5.0 Lollipop) and it always tell's me to make clean. Once done then it wipes out my driver setting I had set to compile the kernel with and pushes the kernel back to stock settings. I am attempting to get my TP-LINK W722N working with Kali (Linux Deploy) via USB OTG.