There are problems with the img-files from Russia-maps from Navicom:
"syzygy writes about these img-files:
Firstly, the first byte of the extracted map is 0xff in hex which is not accepted by GMXT, GMPC and Nuvi. You need to convert each byte wth value V to the value V xor 0xff.
Secondly, after the above conversion the signature at offset 16 is "ASKIMG". You need to change it to "DSKIMG".
Both tweaks should be easy for Caty, but your mileage may vary. :-)"
These tweaks exceed my ability, I was asking for an explanation how to do here on noeman but did not yield a result.
Now I tried this: I extracted the img-file from a download of map of Russia from Navicom, simply droped the img-file onto "gimgxor.exe" and that did the job!
Marvelous! After that I did unlock with "gimgunlock.exe" and now I can see Russia on my nuvi!!
I AM LOVING IT!!!!
I do not understand how to use it. Maybe someone will step by step it clear to me