My Volumio system is build on RPi and HiFiberry Amp+ (geniue). Everything was working perfectly for last two years.
I just upgraded my RPi 3 B to new RPi 3 B+ v1.3. To have fresh system I flashed recent Volumio image -> volumio-2.457-2018-09-17-pi.img.
Unfortunately on boot and I received Undervoltage detected error. And Volumio is now not working of course.
The RPi is powered from HiFiberry and on pins 2-6 on GPIO I have nice stable 5.02 V - tested with multimeter and oscilloscope.
I’v checked the problem with high quality AC Plug power supply and with Lab desktop PSU. Same results.
I’m electronics engineer so I’m quite sure that problem is not on power supply hardware side.
Then I flash latest Raspbian -> 2018-06-27-raspbian-stretch-lite - zero problems - zero undervoltage warnings.
Then i flash latest LibreELEC - upgraded to 8.9 (Leia beta) - works perfectly even with Full HD 3D Avatar (30GB) or HD Netflix - zero undervoltage warnings.
Tested also with -> volumio-2.382-2018-03-16-pi.img and version 2.389 (via PINN) - this same error.
Any ideas what to do ?