It is using s2api, at least the information using dmesg gives this info. Maby the api does not support dvbs2 streams, although i see information about tuning to a dvbs2 stream? I tried to get the tvheadend logging but is does nog give me any more info. The Terratec S2 HD should be supported in the linux kernel by default. Is there a way to compile and use a kernel which uses the latest stb0899 drivers which I understand is used. I shall post the logging asap, do not have enough time at this moment.