There are several scenarios where flashing becomes necessary:
If the phone won't connect, try plugging in the cable while holding the power button or removing/reinserting the battery. Why Flash Your Nokia RM-902? Remove Forgotten Security Code/Password Fix "Contact Service" Error Resolve Screen Freezes or Logo Hangs Update Software Version Improve Phone Performance nokia rm-902 flash file
Clears forgotten patterns, PINs, or privacy passwords. or privacy passwords.