there is a sensor inside the N900 that can tell if the slide cover is open of not

open and close the shutter on the camera
now open an xterminal and run

dmesg

the last two lines should read something like

cam_shutter (GPIO 110) is now open
cam_shutter (GPIO 110) is now closed

Ive had exactly the same issue.

I uninstalled the enhanced kernel version 42 i think - gone back to nokias - restarted and slide the cover and yeepee my camera was working again.

Crispy

PS didnt have the card lines in xterm even after getting the camera working

Hello people...
I had the same problem - my camera app was not launching when sliding the camera cover. How it happened... I needed to change my SIM card. I removed the back cover of the phone. Little later I found some little black rectangular piece of plastic on my table. My first thought was maybe it's something from the phone... Well I did not find any missing parts on it. Little later I discovered that my camera app doesn't start when opening the camera cover. So I started to search over the Internet for solution and I found this discussion. When I read about the magnetic sensor I understood what this little black rectangular piece of plastic was... This is the magnet that stands under the tilt stand and serves to hold it when it's closed. Thank God I found the magnet on my table! I put it under the tilt stand, I opened the camera cover and the camera app launched! Next I need to do is to glue it up on the back cover of the phone, where it fell from...
Nokia should think about other way for detecting when the back cover of the N900 is removed, because obviously the magnet can detach and fall from the back cover and when it happens, we cannot use memory cards and the camera app wont launch when opening the camera cover. What would happen if I did not find the magnet on my table? I'm lucky this time, but maybe the magnet will fall again and I may not find it..

Originally Posted by sifo

i wish i can help you but what i can say is if you want to reflash first try KP50 and if didnt work reflash then

Good luck

./sifo

Originally Posted by vi_

It sounds like the lens cover sensor is kaput.

Can you download 'healthcheck' and look to see if it is registering the cover open/closing please.

Originally Posted by nicholes

i install the healthcheck it tells "open"

and i removed my paper which i put to make lence to be opened always.

OH! the camera works again dramatically!

and healthcheck shows correctly open and closed too.

well i dont know how it happened. but i can confirm that it was not working before, but worked when i put a paper on it. ( i was using paper since i started the thread)

BTW i will update when problem comes back.

CHEERS!