So. If anybody care. Pin of sd-card slot that responsible for write protection just takes off from PCB with contact pad. And there is no any wire to connect to pin. Transitional hole right under contact pad. So, to repair it you need unsolder sd-card slot completely, extract wire from transitional hole and connect it to ground to switch off write protection for ever. Then solder slot back.

Write protection swith on sd-card is mechanical. Its state is read by swith in sd-card slot. So there is nothing to do with sd-card. I have same problem and some time i has had workaround inserting card proper way, but not today. So, i will disassemble camera and disable this switch totally.