As has been mentioned both in this thread and also elsewhere, we can't possibly support reflashed Radeons. If they work for you, then great. If not, well, then it's really too bad.

However there is one thing you can do. I of course can't promise that it'll lead to anything at all, but if you or anyone else who has a card affected by this problem can open up the GraphicsBoards utility and take a screenshot of it (while using the affected card, of course), then maybe that could give me a hint.