I am in a complete muddle over this problem - I bought 3 ds lites for my nephews n nieces and 3 r4ds carts with 2gb memory (I have these for my own kids and they work a treat so I do know what I am doing!) Of the three ds lites two will take and work with the R4's but one will not recognise cart - it says no ds cart inserted - this happens with every R4 I put iinto this particular ds lite - but the other 5 ds lites all take the carts and work fine - I can use normal nintendo carts and they work fine just not R4 - help as I have a very disappointed 9 yr old girl who cannot understand why this is just happening to her - all the evidence proves it is not the R4 or micro sd thats in error as the R4's work in all the other ones - thanks Tracey