Yes, I thought about this possibility, but lock was not enabled, I saw the red and light blue LED, not white blinking
TEST I just did to find the bug again, after remembering I was about to test it with CD player and my amplifier as standalone SPDIF converter and wanting to compare sound from my amplifier headphones ouput and the one of the Tone2 Pro:
I was using the Tone2 Pro connected to both computer and power supply, and SPDIF from CD player. Input is set on Auto. RCA cable go to the amplifier.
- launch playing from computer, able to control the volume.
- then launched the CD player, stop playing on the computer, so the Auto input selection make it goes to SPDIF and the CD is heard. Able to control the volume.
- once I decided to compare headphones outputs, I disconnect the USB cable between the Tone2 Pro and the computer to leave the power supply only and making it work as standalone converter : still able to control the volume.
-
entered the menu and selected SPDIF manually as Input = bug came back : volume goes from O to full to O to full when you rotate the wheel
One more thing I just discovered : I have no possibility of changing headphones Gain, the led is all red, whithout a yellow dot indicating if your in Low Gain or in High Gain.
No, I plugged it back on computer only, and still all red in Gain mode, with volume going random while rotating the wheel, like no sound to maybe 30%, then 0, then 100% then 0.
It’s like selecting SPDIF input manually has bugged my headphones output once again, but now, it stays buggy even after connecting on computer.
No Gain selection possibility, and volume being random when rotating the wheel. Can’t use it with headphones anymore 
Just tried to update the firmware with DFU Tools, it was OK and reset it (device is now set @44.1 in the Dashboard while it was @96) but same thing, no Gain adjustement.
So if it’s a bug, it’s not in the XMOS chip but in the other chip (mine is a second batch device, starting with 11A…)