Usb powered mini v4 with spdif out

I want to power my up2stream mini v4 via usb (mainly cause I use as input source the usb dac only). This works in general (I get wifi, analog ouput works fine).

But when connecting the spdif-out board, I don’t get a signal. The red led of the optical connector remains off.
When I connect the mini v4 to a 5V power supply, the spdif-output works.

Do you know a workaround so that I could use the spdif-out board when the mini v4 is powered via usb?

Hi, the USB Audio input has some conflicts with the SPDIF out in this system, so it’s not available when you select USB DAC mode.