I`ve just bought my new ds real card. I have formatted the memory card and reloaded the software , As per the guide from this site. When I slot it in the game etc it says "there is no DS card inserted". The new m3 ds reader card is different from the last as it is side loading. Come on guys give us a clue.
The side loader is the new build - I have had a couple and they are fine. If you have set the software up correctly (download 4.2d from the site in my siganture) On your card you should have 2 folders SYSTEM and NDS (in the NDS should be the roms - all .nds nothing else) If this is OK then it may be that the card it not hitting all the pins in the ds. Take out the SD card once or twice to make sure it goes in nicely, push the M3 card in and out of the ds a few times then see if its registered, if it isn't then try the paper shim trick, put a thin piece of card (or paper folded over) between the M3 card and the back of the ds (pushing the card onto the ds pins) Hope that helps