I got my DSTWO a few months ago; it worked from the start without problems, but it has slowly developed a booting problem over time. At first, I noticed that sometimes refused to start, giving the black error screen; I figured the cart/SD card seating was the issue, and reseating seemed to fix the problem. However, it didn't always; and sometimes, it never worked with consecutive 3DS boots. In trying every option, I discovered that leaving the system off for five minutes (regardless of whether I touched the cart) would just about always get the cart to work if I chose it immediately after startup. It usually wouldn't work otherwise. Now, it never works unless I wait 10 to 15 minutes with the 3DS off before getting one shot at getting it to work. This seems like it might be a defect in the circuitry, perhaps related to some improperly stored charge. It could be related to otherwise immaterial stuff inside the 3DS as well; I won't be the one to find out. In any case, I have no reason to believe the card formatting or contact cleanliness is the issue; also, I have gotten the cart to boot and play a game at least once since the cart V1.20 firmware update and 3DS 22.214.171.124 update. Does anyone have any ideas of what to do? I have seen at least one other similar report on the internet about having to wait with a DSTWO in order to boot it.