The solution is said to be "iw set reg EU" but that doesn't help you if you don't have the "iw" package installed and you cannot connect to the Internet because the WiFi access point you need to use is on channel 12 or 13.

I was able to get access to channel 13 without iw by doing

Nokia-N900:~# rmmod wl12xx
Nokia-N900:~# rmmod mac80211
Nokia-N900:~# rmmod cfg80211
Nokia-N900:~# modprobe cfg80211 ieee80211_regdom=EU
Nokia-N900:~# modprobe mac80211
Nokia-N900:~# modprobe wl12xx

http://wireless.kernel.org/en/developers/Regulatory

The command "iwlist wlan0 freq" will show you what frequencies are currently allowed.

I tried doing "iw reg set JP" but it did not seem to activate channel 14. Don't forget the WiFi Channel 12 and 13 enabler package

I have a 2.6.28.10-power51 kernel.