I am a newbie still trying to learn the ropes. Having had much success with OSM and OCM for cycling and walking I thought I would try my hand at updating my vehicle SatNav.
The information that I have been able to discover so far is that Garmin devices like to have the map called “gmapsupp.img”. Unfortunately, the built in Kenwood DNX521DAB machine keeps all its files out of reach of the user. Once has to put updates on a data stick, plug it in and then select ‘Update’ from the options and the machine will either do it or reject it.
As the first part of an update the machine will write the following files to a blank data stick:
*** this file is altered at the time of the first stage of the update. The rest seem to be ‘permanent’
According to the information I have, the next stage is to add the map file to the GARMIN folder and then offer the datastik to the machine again. This I have done with a map file called “gmapsupp.img”. The machine sees it but report map format invalid. I assume that really means that it has the wrong name for this particular device as the map is a download from a respectable OSM publisher and marked for Garmin use.
Any suggestions for a fix would be welcome.