The latest Herries firmware, 108v3-2 I think. In the NEC forum I posted my problem a few days ago (lol.. nobody was interested). The burning speed never went over 3.1x.
I decide not to bother testing various firmwares. My benQ 1620 just arrived and it burns Teon E01 fine @ 8x. Maybe I'll test overspeeding it later. But anyway the preliminary result looks good. I paid ~12$ (including tax) for 80 discs, and I don't feel like to ask more.
%% But I'm still interested in distinguishing between MCC and CMC for the future. It seems that nobody knows how.