Thanks for the reply, I have an SE versions of most v8 navcore's so will look up 8.351 here so will take it out of that, does the mctx.txt file also need to be changed as there is no mention of the USA in it. There is also not an mctx.txt file in my 8.351 either. Also what about the gns folder, would this also need to be changed to match the dat file?