g928t Writes CERT. Restarts and says 000000

Hi Im Trying To Write The CERT. File onto the g928t the firmware is 5.1.1 OI5. it says successful when writing imei cert. but when it restarts it has original imei and now it says phone has been flashed with unauthorized software. any idea how to fix it?

P.S I Have more then one of these phones doing the same thing