3410 ask for security code when keypad is locked

Hi,

my 3410 is asking for a security code ONLY when i'm trying to unlock the keyboard. then, i enter a mastercode (as someone obviously changed the default 12345 code) and suddenly, the phone ask : 'INSERT SIM'... whereas my sim is already inside, and i could use it perfectly just before the keyboard locked up....
The only way i can unfreeze the phone at this step is to take off battery and restart...

that's weird, i'm not newbee in unlocking phones, but i canno't figure out what's goind on with this 3410.
Any ideas ?

Thx.

There is a menu to turn of the keylock security in the settings menu.
You could always do a full factory reset with a MBUS cable. It will also reset the security code back to 12345 as well.