1. First do a CUSTOM reset: *2767*2878#
2. Take a wrong network SIM and insert a half of it, with the battery semy lifted up, so when you turn on the phone it don't detect the SIM. Very important so it won't ask for network password and shows "Insert SIM" message.
3. Now you can fully insert the SIM without turnig off the phone, at this stage the phone is still asking to "Insert SIM" with the WRONG SIM inside.
4. Make a FULL reset: *2767*3855#
5. The phone should reboot working with "wrong" sim inside.
6. Change the NCK password to 8 zeros: *7465625*638*00000000*00000000#
7. Disable network lock: #7465625*638*00000000#