N915tuvu2cok2 5.1.1 cert writing??

Hello Customer came in with this phone the other day.

GALAXY Note Edge SM-N915T TMB N915TUVU2COK2 5.1.1

Trying to write the cert but MSL wont reset.

I’m sure I’ve got to downgrade the modem to "BOK1/BOG2" etc or something along those lines.

I’ve yet to find one. Could anyone help me out please and thank you.