Updating units

[RA8R55]

I currently have 2 elite7ti unit on my boat. I have updated my console unit wirelessly and all is good. My question is, can I update my bow unit with the same SIM card? Or do I need a separate card.? Do I even need a card installed my bow unit at all? The SIM card in my console unit has my navionics maps on it.
Any advice would be appropriated

[Ken Sauret]

An update downloaded from the Lowrance web site for a certain model should work in all units of that model.