Hi Felix,
I just played around a bit in Mapsource, and couldn't notice ANY difference. If routing does not work somewhere without this patch, it will not work either with the patch. If it works without patch, it does so with patch too. (I installed the otherwise exact same map twice in Mapsource, setup routes and then change maps and click on recalculate). The chosen ways are also 1:1 identical.
That's OK - at least it didn't break anything.
I have yet to try on my Vista HCx. Are you sure that there was a difference on the NUVI? Did you really install the otherwise exact same map twice (of course with different FID)?
I processed the same map data with and without the patch and put the results (separately) onto a SD card. I observed different routing behaviour for the two maps - not a big difference, but definitely a difference.
My sample map size decreased from 67.3MB to 65.5MB. Compressed with 7-zip the size decrease is less (46.4 to 45.8 MB)
OK. Thanks for the feedback. Cheers, Mark