I wish I knew that before I formatted the card. Currently downloading 550GB super slowlyYou can copy everything from your memory card to your pc, then put the card into the new switch to format it, remove the card from the switch then copy the contents over from your pc back to the card, then put it into the new switch.
Mine still isn't due till next week and I also purchased it from Amazon France.
That's funny as I only ordered mine on the day the DF overview video came out.