Did you get the datasheet yet?
http://www.macronix.com/QuickPlace/hq/PageLibrary4825740B00298A3B.nsf/h_Index/6F878CF760C559BD482576E00022E6CC/?OpenDocument&EPN=MX25L1606E There is sample code to get you started. Also there is the document on migrating to 1606E which should be helpful, if you have some working code for the 1605D. I believe the FreeBSD people have some MX25L support...