It seems that a "possible" cause for the missing telephonic function is a factory misplaced transistor V2099 as described here:
http://www.elektroda.pl/rtvforum/topic2095031.html
Translation is more or less:
"...If the phone starts noticeably longer than usually (about one minute more), it means that the V2099 transistor (in photo) is not activated by a signal from the processor CMT_EN. Despite this, the phone passes the test in local mode... "
This is probably picked from a Nokia bulletin.
At the end is said that repair is not possible/suggested - economically speaking i suppose.
Could it be that after a few years of mechanical stress it looses his original uncertain position? ..Who knows?!?