Well, the 59 emails exchanged with Terratec users finally paid off, at least for the version of the product that uses the zl10353. With the help of Simon Kenyon, who was nice enough to let me SSH into his environment for a few hours, I was able to identify the problem, which ended up being a misconfiguration of the i2c gate for this board. To make things more confusing, setting the i2c gate parameters on the zl10353 when there is no tuner behind the gate actually wedges the i2c bus. As a result, the xc3028 initialization and first tuning attempt would go through, but after the first call to close the gate gets all subsequent commands would get dropped.
If you’re a Terratec user and you have the version with the zl10353, feel free to try the following tree and provide feedback:
I’ll do some cleanup on the tree and issue a PULL request, and will continue trying to work through why the mt352 based board doesn’t work.
I also cooked up a remote control profile for the EVGA inDtube board, which I think officially brings that work to a close.