Here's some codes and tricks I've found useful while deploying a Cisco WLC - Nokia Dual Mode architecture.
These apply to th e series phones.
To see the phone's WLAN mac-address :
Check behind the battery, or
*#62209526# (mnemonic trick : it is like writing "*#mac wlan#" with T9) will display it.
To reset to factory defaults, get to Tools->Settings->Phone->General->Orig. phone settings
The default unlock code is 12345.
There is also a code to reset the ROM and the factory defaults, without deleting data files : *#7780#
Then there's the Deep Reset code : *#7370#
This one resets factory settings, deletes every data file and uninstall everything. This reset asks for the unlock code too.
To read the phone's IMEI : *#06#
To check the phone's firmware version the code is *#0000#
Then determine if firmware version is up to date : http://europe.nokia.com/A4577224