You won't save them to your map chip. You will have to get a blank micro SD card with adapter. Remove map card from old unit. Install blank card in old unit and download waypoints to that card. Then remove micro card from adapter and install it in your new unit then transfere the waypoints to new unit. Once installed the will overlay on your new map card just like they did on your Navionics card. Way points are not saved on your map card. As far as your second question I don't know the answer to that one.
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Charlie Weaver USN/ENC 1965-1979