If you read that whole thread from head-fi I posted, the manufacturer talks about the DAP. They were bringing up that they hoped whatever it was, it could be ROCKboxed, etc.
I did slog through the whole thread; they did not define what "HD" was supposed to mean, nor discuss in detail any of the technology they plan to use.
Going over the whole thread a second time, James at Fiio said the DAP will not be expensive and then this:
2410, but we can only ask our supplier to design the firmware as our request! so I am not sure whether the term can develop such version! btw, our supplier design software to many famous international brand, like Philps and TEAC!
We can not get the original SDK and I am not sure anyother person can get that! it is a special solution and that is why I said it had not been used in any other portable DAP!
so I'm wrong about the Wolfson 8740. Still could be some other DAC never tried in a portable solution. Thankfully, it seems we also won't be seeing another SigmaTel chip (*cough* AMP3 *cough* Hifiman *cough*) disguised as an "audiophile" solution.