Hi i just answered a call on my n900 and after i ended the call, my n900 stopped recognizing the sim card. I rebooted, checked to see if it was in gsm mode, nothing worked. I have put my sim card in an other phone and its working fine. So, the problem is with my N900. I am running PR1.3 and i have overclocked it. Its been running fine since many a month now and i have not installed any apps in a while too. It was not overclocked when i last answered a call, it was at the default 600MHz clock. There is strike mark against the tower logo shown where it displays the signal strength in the top menu. All the applications are working fine though. Kindly help me. Thanks.

Never mind, the paper trick did it.

paper trick?? huh?

putting a piece of paper between the sim card and the door, i assume

The paper trick also worked wonders on my N78. My Cingular SIM was a wee bit thin so I backed it with a piece of index card cut to shape. (Note: the paper covers the back of the SIM, not the contact side! )Then the N78 worked for both the T-Mobile and Cingular SIM. I then promptly boxed it up and sent it to the repair center. I'll not be using such a cheap trick when trying to get a new $300+ device to work. They replaced the entire SIM module and no more problem. This was on two of the several N78-3 devices I've used.

I'd have no problem using this if the problem developed out of warranty.