NDS R4

Question

Hi - I was hoping you could help. My daughter has a R4 loaded with games - however most of them dont load up and the NDS says "can not find data - switch off and reinsert card" - However I recently purchased anther for my son and came across same problem. After visiting this site I upgraded my sons and that has fixed the problem 100%. I therefore tried the same with my daughters and was unsuccessful as now the R4 doesnt load up at all not even to the menu. Just stays on black screen "loading". I thought I would try deleting all from hers and copying my sons across. Still with no success same problem. Strange thing is that when I put my daughters micro in my sons R4 it works 100%. When I put my sons micro in my daughters R4 - no good just same black screen "loading". It is as if there is a problem with R4 and not the data on the micro. Yet her R4 was working ( not correctly ) before the update.... Any Ideas????