the only fix I found after surfing around for it was to use it as a music player and find another N900 and another and another..
Sorry to hamster away all those N900 while they were cheap

Defects I have encountered so far on various, not same N900:

-GPS not functioning
-All telephone functions disabled turning the phone into a surfing tablet / music player.
-Display messed up (booting but rubbish on screen)