Way back in September, revision 1228 changed one of the routing data structures (Table A) to have one entry per road rather than one entry per arc (a road contains 1 or more arcs). This reduced the number of Table A entries required which made the maps smaller and, hopefully, improved the routing because the routing centres could be larger. However, I have been trying for some time now to find why the routing is partially broken on my Nuvi 255 for certain combinations of mkgmap version, extra patches and the options used when compiling the map. The same maps work fine (as far as I have tested them) on mapsource and the etrex. Not one routing failure occurred on those that could not be attributed to something else. So, after much dicking around with options, patches, etc., I think the Table A size reduction is the culprit. The attached patch essentially undoes the good work from September (although this code is simpler than what was there before). With this, the Nuvi barfs no more. The downside is that the map has grown again. Can't say whether the routing quality has changed. Rolled into this patch is another reversion. The value of MAX_ARC_LENGTH has been reverted to 75000. Never did believe that was the real solution. Please give it a go and report any findings. Mark PS - Marko, please try this and see if the routing problems you were experiencing still occur. Also, please try it on your Nuvi user and see if their problems go away. PPS - the one pleasing aspect of all this is that if it proves to be a sensible change, the node-reduction patch that I keep banging on about will see the light of day.