I'm following your instructions but something is not clear:
At point 5 is written: 5. Extract the downloaded file and put all files into the ROOT of the USB/SD CARD
If I extract the downloaded file NG4-N42c.zip I have a folder named NG4-N42c
Inside NG4-N42c folder there is another folder with the same name NG4-N42c
Inside this second NG4-N42c there is another folder HEADUNIT and a file HBUPDATE.DEF
Inside the folder HEADUNIT there are 14 folders and 3 files.
So, what do you mean with "put all files into the ROOT of the USB/SD CARD"?
This is the version of my NG4
View attachment 11377
I think it is the original one from 2010
Nothing wrong with the GPS that indicate -10m ... I live in the Netherlands