My early serial numbered unit came back from service today after they "flashed the PCB" to fix the LED color issue. The good news is that now MQA always shows magenta, where before it seemed to be randomly yellow or whatever.My Diablo works fine on a stock 7.0 firmware. All led colors are correct: mqa - green, mqa studio - blue. Running it out of ROCK on NUC (Roon Linux based OS).
I tested Diablo using PCM only (no DSD) to discover that indicator colors have changed, but are still not correct:
44kHz and 48kHz files result in a yellow LED, not green as described in the literature.
Other sampling rates produce white, not green (88,96), and not yellow (176, 192, 352) as described.
I did not try 384kHz (supposed to be yellow) or 768kHz (supposed to be white).
All could be forgiven if the promised MQA decoding through SPDIF input had been enabled, but that didn't happen, either. Oh well.
EDIT: I do get green with basic MQA and blue with MQA Studio at any sampling rate (as qsk78 says above) when not using DSP after Roon does the first unfold.