Go to the site http://unlockme.co.uk and enter your phone’s IMIE number and press Enter then u’ll get the master code of your phone.
2. This master code can be used as lock code when we are asked for the security code.
3.But always we can’t remember master code and we want to use an easier lock-code then we can set a new security code of our own wish by giving the Master-code as our old security code when asked for old code while resetting security code.
Tools -> Settings ->(scroll down) security -> Phone and SIM ->(scroll down) Lock Code
Then it asks for old code where u can type the master code and then set the new code as you wish.
When during formatting u are asked for lock code you can also enter Master code.
To get IMIE of your phone type *#06#
on screen of your phones.
All credits goes to Dejan Kaljevic
who has designed many procedures to calculate the Master codes for Nokia phones.
To know the security code of nokia phones you can also download a software for nokia series 60 phones:-