I am concerned about the use of this config.txt setting to suppress low battery voltage.
I have successfully fed power to several raspberry pis through the GPIO pins and never had to use this setting.
I think there is insufficient regulation to supply the peak current required by the PI.
Even if the warnings are suppressed the Pi will slow its clocks until the power stress is removed.
Additionally I would only supply the Pi with an absolute maximum of 5.25 volts.
It would be interesting to see if adding a suitable cable from the USB power port on the Pi to the regulator in the sBITX also eliminated the warnings.
