I have a TT One XL from MY 2008. As I am frequently updating my maps I thought I should also update my NC. I tried several different NCs with no good results. On NC 9.170 my unit started working very slow. With 9.061 I couldn power my unit on without ejecting and reinserting the SD card. In the end I found out that the best NC is 8.010. My One XL runs smooth and nice with this NC.