I've just noticed that I cannot play some games or the graphics are garbled on my TG-Everdrive. For example Batman or Aio Blink. To ensure that the roms aren't the issue, I've loaded the roms with my 20 year old Multi Game Doctor 2 and they work fine. I have the latest OS installed on my TG-ED. How can I ensure that the onboard flash-memory is ok?