I had quite a few errors when I got the unit back, Nav database and SVM amongst others, cleared the SVM with the usual method and deleted all the DTC's but some came back after driving the car, then I cleared DTC's again and they stayed clear but I have not checked since.Presume it's not giving you navigation database errors now ?. I've been clear of them - result of time being up on the Mapcare FeC. They left me with SVMs but I decided I would not attempt to remove them this time. In reality nobody cares about SVMs.
The FeCs (firmware enabling codes) are really parameter files that are read in to make the software behave in certain fashion. The firmware loaded up is the original.