When I code echo $OSSO_PRODUCT_WLAN_CHANNEL I get an empty line in reply.
So, when I'm next in Europe (June 2011), if N800 won't connect to wifi after the default_country has been reset and wlancond restarted, I'll try the effect of Code: OSSO_PRODUCT_WLAN_CHANNEL=12 or 13 if that still doesn't work.
OSSO_PRODUCT_WLAN_CHANNEL=12