I can report failure of one suggestion from the old thread. I quoted lardman's UK-purchased MAC address to download a FIASCO image of the latest DIABLO, which I then flashed to my N800. (Although this was deceitful, I can not find anything in the Licence Agreement that makes it illegal.)

default_country is still 0x10.

OSSO_PRODUCT_WLAN_CHANNEL is still 'FCC/US'.