The Sharp ROM's network applet appears to be inferior to the one used in Cacko releases in several respects. Notably:
The Sharp ROM can crash if the network card is removed at the wrong moment
and
When the lid is closed and then re-opened while a network session is active the Cacko ROM will automatically re-establish the connection but the Sharp one does not appear to do so.
Is there an upgrade that can be installed on the Sharp ROM? - I've got a C3100.