i own an r4 sdhc dual core (r4isdhc.com) and the r4 gold pro (r4i-gold.com). both of my flashcards don't go into sleep mode in my 3ds or xl, instead when closed they play distorted noises from the games they're running and stay on. this is weird because i've also got an r4i 3d (r4igold.cn) and this one supports sleep mode fine and all. has anyone experienced distorted noises coming out of the dsi while it's supposed to be in sleep mode while using flashcards? if so were you able to fix it?