Hmm, one change I discovered now: if the N900 is connected to a WLAN, JoikuSpot doesn't even try to start a connection, it says to close all active connections first.

Can't test the reboots right now, will do it during the day (thinkpad) resp. this evening (mac). With the "old" firmware I did have this problem with a macbook pro but never with a thinkpad x60s...