It is work (say another word - tested) only with most of handhelder from Garmin which be updating by *.RGN files with updater only - GPSMAP and eTrex and other old model like Geko, Foretrex and other.

Translate and read for some detail:
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Address or region probably is given from RGN. May be it is works for Nuvi by upodater.exe. I do not test it.

I have programm code for this programm and if you need in it I may send it to you by PM.