I just recently bought the avic-d1 of ebay and everything was working good untill I decided to try the updated east coast 2006 map disc that a friend of mine had for his avic-n2, just to see if it made much of a difference.

Now the problem is that my d1 wont read the original discs that came with the unit, the 2005 d1 map discs.....

IS THERE A WAY TO FIX THIS, OR DO I HAVE TO BUY THE NEW 2006 UPDATED DISCS FOR THIS UNIT NOW????

If so, do you think it would be worth trying to sell my original discs?

Sounds like you may have to do a "force read." Search for that and the instructions you will find.