I've just upgraded my fone and i've given my mate my old one cause he wanted it. Its a nokia (but i've forgotten what type but fairly newish (ie in last year or so)) but its not working with his sim card and says he needs the PIN for it. I thought it was 12345 or something but apparently its not and i've forgotton it...

HOWEVER it works with my simcard fine, it works with my brothers sim cards and its not locked or anything.. would it be his sim card?

He's rang up optus and nokia without much luck..

Anyone know what to do?