'Low Voltage' on Pi via MiSTer, but GPIOs reading 6.15-6.2v ?

[Higgy69]

Hi,
As subject I have a separate Pi 3 that I mounted a USB 3 breakout board to so I just plug in a male-male cable (It is 1m long).
Everything seems to work fine, MiSTer OSD etc.
But I am getting the Low Voltage error. I am powering the MiSTer via 5v 6amp supply and I measured the voltage at the Pi's GPIO pins and it is between 6.15-6.2v.
So why would I be getting the error?
Cheers

[dwhinham]

Where precisely are you putting the probes? On Pin 2 and Pin 6 on the Pi's GPIO?
If your meter's batteries are dying then it can become inaccurate, might be worth checking.

It's extremely unlikely the Pi's firmware is lying about the low voltage situation, I'd be questioning the measuring equipment and test method.

[Higgy69]

Face palm. Yep multimeter's 9v battery was low. New battery and we have 4.75V
(I was using pins 4 and 34 to measure)