is flashing Sprint Note 4 possible?

I keep getting red x / no service... the issue I believe is IMEI cert via *#0011* showing failed. From what I've gathered, this was introduced around S5 & Note 3 timeframe. Downgrading modem to MI3 works since this security had not yet implemented until after. But is MI3 radio compatible with Note 4?

Otherwise obtaining a cert is very unlikely? Or write super IMEI, has this been discovered yet for Note 4?