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?
I have no test for memory, i use games for testing. It may happens if rom files is fragmented. Try to copy those games on clean sd card, also you may send them to me, i will check on my system also. Region mod is another possible reason, is your system region modded?
Besides the SD card being fragmented, you might have ROM images that the OS doesn't like. I can't remember as it has been so long. I know Batman works, I played through the whole game on my Turbo ED.