Not sure if you saw the new unfolding drama, but today Stephen Leary officially deleted all of his YouTube videos and has apparently left the Amiga hobby scene for good.
He dropped a video about 4 days ago with the promise that when it hit 1,000 views it, too, would be deleted. I caught it at 985.
Some time in the next 30 minutes it was gone as was his channel.
So if you are after a TF534 it'll have to be after-market. Well... actually, maybe not. That's partly the reason he decided to quit. Apparently someone from Poland who relocated to Germany was cloning his boards against Stephen's will. So there may be more TF cards out there after all, but without any future support or updates.