I have a SMS Japan + the adaptor sold at http://www.smspower.org/Shop/GenderAdapter I just received my MasterED and I plugged it in on the back of the GenderAdapter, it starts up fine showing OS v4 so I decide to flash it with OS v5 ... it works good. So far so good but then when I try to load any game (any game at all) I can only seen the countdown for the flashing up to 0, then the screen goes black and nothing else happens. I tries power off then on the SMS and the MasterED menu appears again. I can go to start game but same thing, just black screen. I tried to downgrade OS to v4 but nothing happens. The OS flash utility scren tells me "(Left) No (Right) yes" but it will not let me chose right, so I cannot downgrade to see if the incompatibility is with v5. Any help greatly appreciated, the fact that the MasterED menu shows up and that I was able to flash OS v5 sounds promising, now I need the game to work.