Model : All SonyEricsson

1 - Switch ON your phone without SIM Card,
2 - Press the left arrow 1 time,
3 - Press the button * 2 times ,
4 - Press the left arrow 1 time,
5 - The message "Personalize with MNC2" will appear,
6 - You can now enter the Unlock Code.

If your phone have a "JOGDIAL" (eg : Sony Ericsson K700i) you must press "down arrow" instead of "left arrow" for step 2 & 3. We mean by "Down Arrow" to direct the Jogdial down.