It would seem a couple of us are having the same issue. That is, the n900 powering on as soon as the battery is inserted. At first I thought this was due to a dodgy soldering job I did on the USB port however it seems other people are reporting the same issue with 1 person having not soldered the USB port. Which of the people who are facing this issue are using cssu-thumb? Does setting RD flag 'power_button' actually workaround this problem?