mobile

Is it possible to go back to stock kitkat 4.4.4 ftf from a stock lollipop 5.0.2 without having any issues like losing imei number or any other problems? My xperia z ultra 6833 was not upgraded from 4.4.4 to 5.0.2 with Ota. I flash with a stock 5.0.2 ftf via flashtool
Thanks