What's wrong with my R4i cart?

Recently my old MicroSD got corrupted due to a bad rom and could not be used on my R4i which is this one> www.r4i.ndsi.in I got another MicroSD and put my old roms and save files there which were once in the corrupted MicroSD. The games can be played but i noticed that there is more lag on the main menu when i'm choosing a game to play and although cheats show up, they do not in any way function. Is my cart broken? And if it is, is there any place I can get a well known brand for an R4i cart in Singapore at a good price?