I just installed the Ford navi, '08 HU, in my 04 but I got 4P version of DVD from ebay and the system said incompatible with the unit Is there something I have to do for initial setup with DVD disk or what??? I figured newer unit will be backward compatible with older disk but not so....4P disk appears to be scratch free and in great condition....any help please....

 

If you want to try this you can, but be careful with your parts and wiring... try at own risk ...

I have heard of a similar problem before. It isnt a compatibility issue. The DVD reader within the unit has had some problems before. Try this. Try taking your unit out of the dash, keep it plugged in tho. Take out the DVD disk now with the units screen facing the sky put the disk back in. Gravity helps some how get the disk further into the unit so the DVD reader can read it. You will be putting the disk in downwards. Try it a couple time if it doesnt work on the first try. Let me know if it works for you.

It might be however that a 08 nav unit isnt compatible with the older
4p disk, but i dont see why Ford would make it that way.