after changing phone product code i found my previous Lock Code (19855) is reset ed To nokia defult code (12345)

im tested this tip in my another phone (5700) and same Result !

Yes ! i can Reset my Lock Code If i forget it

Becarefull and do this Step-By-Step ! ( do steps 6 and 8 Carefully)
im not responsible for any thing in your device !
successfully worked in my N73 + 5700 and my Friend ’s N91 !

1: download a nokia Flashing Tools Called (Nemisis Service Software)

from : [Only Registered and Activated Users Can See Links. Click Here To Register...]

2: Install it ! (press Next Button in installation and dont change any Setup Setting)

3: Plug your Phone With Usb and Select “PC Suit” Mode . and run installed app in desktop .
its shortcut name is “NSS” in your desktop !

4: Follow my first screen-Shot (1.bmp) :
in app main window (right corner and Top) click on a Magnifier Icon (Scan For New Device)

5: Follow second screen-Shot (2.bmp) :
in app tabs click to “Phone Info” it has a 6600 icon !
and then click to “Read” Button in Right Corner Similar to screen-Shot !
u must see Three Field With Values !

6: Remember First Value that Called “Product Code” (dont Forget it !)

Follow 3nd screen-Shot (3.bmp) :

Change First Field “Product Code” To a S60v3 Valid COde Like “0529785″
check that Check-mark Showed in Screen-Shot ! ( first check mark)
then Click “Write”

be patient untill operation sucessfully finished and “done” .

7: its better restart device !
*** Nice ! now your lock code must set to “12345″

**** Warning : do this step !

8: at final Re-DO all Steps and Restore your previous “product Code” in step 6 (do step 6 with your orginal product code that Remind it !)
its very important if you want update your frimware in next time !