Sharing map with 2nd plotter



I recently bought two used Furuno MFD plotters (MFD8 and MFD12) and a radar. The MFD8 under deck is full of charts of Europe and is set as master. The MFD12 in the cockpit is set as slave, but has only a map of Norway on it.
Is there a way to access the charts stored on the MFD8 on the MFD12?
I don't have the SD cards with the maps on (they were not included when I bought the plotters)

This is a bit urgent, as we're crossing the North sea in two days, and need the plotter in the cockpit to work :)
You will have to download the charts you want to load into the slave. If you already have an unlock code for the master you will not have to purchase another unlock for the slave.
The charts can be downloaded from the MapMedia website here:
The charts are loaded from an SD card into the hard drive of the MFD. You might also want to go to our website, and update the software for both your MFD8 and MFD12. There is also a chance that the charts currently in your MFD12 might be out of date and a revision is available. Depending on your current charts it may or may not be a free upgrade.
If you are unsure of the processes involved I suggest you contact a local Furuno dealer or distributor for the country in which you are located.
Thanks for the answer.
I downloaded a relevant chart from the MapMedia site and installed it on the slave plotter in the cockpit.
However I don't have the unlock codes, and I can't reach the previous plotter owner. I think the maps on MapMedia is a bit newer than the ones already installed on the master plotter, so I probably have to pay up anyways.

But! - We're leaving for Shetland the day after tomorrow. Is there a way to purchase unlock codes online? We don't have time to wait for a SD-card to be sent by mail...

The map we need unlocked is called 'SDVENM019MMAP07'.
I would recommend contacting your local Furuno distributor with your system ID to find out what charts (and what version) the previous owner might have purchased. Even if it is an older version and you want the current one; you should only have to pay an upgrade price and not the full price for any chart(s) that have already been licensed for the machine. I am sure your local distributor can assist you with ordering the upgraded unlock code. The chart(s) could be directly downloaded from the internet and placed on a SD card. The unlock codes are normally e-mailed to your e-mail address.
I called the local distributor. He was very helpful and provided me with links to download the correct charts, and unlock codes for the MFD12, as it turns out the MFD8 plotter contained a lot of unlocked charts. He could see this in his database.
So, problem is solved. Thanks :)