According to the service manual, the sensor detecting the movement of the keyboard is a magneto-resistive, but no details about the specific model.

I tried to find a kernel module (lsmod) which name corresponds to a magnetorresitive sensor without success.

Also I tried to find a high-resolution image of the internals of the N900, but no luck.

Someone could help giving more specific information about the sensor, or a high resolution image?

This could let us to find a provisional solution, may be commenting out some line of the initialization scripts of the kernel.

Regards,
Àngel