Hi Franco, my understanding is that this is not a bug, but a limitation implemented by Garmin. My mothers Nüvi also doesn't load unicode maps. One reason might be that some indexes don't work with unicode and mkgmap doesn't write the needed ones. I cannot try that now. If the 750 loads a unicode map without an index we may have a chance by doing more reverse engeneering of old maps. On the other hand, I wonder how long they will the support the old img format written by mkgmap, maybe this is the first step to drop this support. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von franco_bez <franco.bez@web.de> Gesendet: Freitag, 25. August 2017 22:18:28 An: mkgmap-dev@lists.mkgmap.org.uk Betreff: [mkgmap-dev] Recent Garmin Firmware "cannot authenticate maps" when they are unicode Hi all, maybe it's already a know bug. I just stumbled over this one: On a new Oregon750 I got the Error "cannot authenticate maps", while on the old Oregon550 the maps worked like always. I found out that changing the option "unicode" to "latin1" in my style did the trick, the resulting maps work on both devices. Over here in Germany I have no problem with latin1, but I suspect that in Russia or in the middle east or far east countries this will be a real problem. I attached the Error Screenshots. Ciao, Franco <http://gis.19327.n8.nabble.com/file/n5901399/IMG_20170818_063414%7E01.jpg> <http://gis.19327.n8.nabble.com/file/n5901399/IMG_20170818_063911%7E01.jpg> -- View this message in context: http://gis.19327.n8.nabble.com/Recent-Garmin-Firmware-cannot-authenticate-ma... Sent from the Mkgmap Development mailing list archive at Nabble.com. _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev