I've no flatrate.

n900 does regulary updates of the software.
I don't need that.

I've tried everything of maemo wiki.

my /var/lib/gconf/apps/hildon/update-notifier/%gconf.xml file shows:
?xml version="1.0"?>
<gconf>
<entry name="blink-after" mtime="1280353508" type="int" value="1440"/>
<entry name="check_interval" mtime="1284968752" type="int" value="20160"/>
</gconf>
~


Nokia-N900:~# gconftool -g /apps/hildon/update-notifier/check_interval

yields:
20160

This should be an update every two weeks. But it does an update every time I connect to the internet after one or two days.