Default [Q] IMEI Not Recovering!

So I downgraded from 4.3 to 4.1.2. Everything works normal except IMEI which is and incorrect number. I backup my efs partition with my modem and restored it, and yet, it still fails to change to the correct number.

So I re-flashed stock 4.3 and IMEI came back again. When I went back a to 4.1.2 second time, the problem persists. What am I doing wrong???

SOLVED: Updated modem partition.