Thanks for answer, Nicolai. If I understand it correctly, raw imagedata is the same, no matter who pick it up (fCam or camera-ui). So, fCam creates .dng file (from mentioned raw imagedata) differently? It is even possible?
Furthermore, CornerFix is FOSS, so there is a chance that it's going to be ported to N900 (which, in tandem with ufRAW, supply us with whole 'photolab' on device).