Version mkgmap-r4375 was committed by gerd on Mon, 25 Nov 2019 Document possible routing problems in BaseCamp when option --check-routing-island-len=INTEGER is used. It seems that the routing problems occur only in Basecamp. My current understanding is that BaseCamp uses a different way to read the *.IMG data compared to devices or Mapsource. http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4375