Replace below files in the rom zip from any 4.2.2 rom where network signals were working fine for you.Anyone facing no network connectivity issue in sims. Sometimes I'm facing issue in both sims, sometimes I'm facing issue in one sim. Just wanted to confirm this is not a ROM issue.
1. modem.img from system/etc/firmware and rename it as modem_1_3g_n.img
2. File named BPLGU..... from system/etc/mddb. After copying delete the other one.
Then reflash the ROM zip. It will definitely solve your problem of network signal...
Hit thanks if I helped you...