my sons ds won't read r4 card, but daughters ds will read it.

very probably a contact problem with the r4ds and ds that cant read it .

is there any dust or dirt in the slot of the ds ?

if not then the paper trick might work , as follows -

cut a piece of thin card the same width as your r4ds but about 1 inch longer than your r4ds .

now put the card on the side of the r4ds sticker and insert them both into your ds .

what this does is very slightly push the r4ds closer to the cotacts inside your ds .

woof811.

The paper trick worked!!! Thank you so much!