Well, after much searching I get the impression my problem is similar to
this one in which case I'll have to flash the phone back to the original FW and EEPROM and take it back for servicing, but I would still appreciate any ideas or views from people here as to if it is the same problem, or even if it is more likely to be a hardware or software problem.
help me obi-wan kenobi; you're my only hope.