Appreciate your answer.
I tried gimgunlock-0.04, didn't help. Looked at a page for "Universal Firmware Patcher", found it's hard to determine what my case really needs plus being lack of time, so I decided not to go for it.
Then I found on ebay there is a map for Spain and Portugal and the price was acceptable, so I bought the map, saved the .img file under Garmin folder on a microSD, so simple, nothing more, and it works!