Sorry I am a newbie and I just got my KDX B005 last week. It has 2.5.4 installed and I went to Amazon.com upgraded it to 2.5.8. You can try here:
http://www.amazon.com/gp/help/custom...deId=201504450
But from here I can see that KDXG should use 2.5.8 also. Don't know how you got 3.x.x. Hope this helps.
BTW, I just installed Duokan today and it worked without any problem.