There is non-volatile 'FADEC memory', mentioned re. SR111:
http://bst-tsb.gc.ca/en/reports/air/...rep1_12_09.asp
and in a mechanics' forum, re. BA038, at:
http://www.airmech.co.uk/forums/show...t=8005&page=13
According to Goodrich, the EECs chosen for the Trent provide 'a wide range of diagnostics data to the engine and aircraft maintenance systems...80% is for maintenance, 20% is for engine control.'
http://www.enginecontrols.goodrich.com/large/ecu.shtml
I don't know how much of this 80% would end up in non-volatile memory.