g920p no service problem

hi gcpro team my s6 is no network i try these steps.

1, full flash repair firmware
2, flash only modem downgrade , upgrade
3, reset network
4, in hiden menu gcf on
5, enable global mode.
6, flash combination but in combination also no network
7, unlock
8, write efs
9, write qcn
but no luck please help me how to solved this problem thanks