@curieos said in 6XD 5V Input Voltage Limits:

If the 5V supply in question were adjustable, and the 6XD were to allow some fraction of a volt over 5V, would it be possible to overcome the voltage drop from the protection circuitry?

Yes. The protection circuitry comprises a Schottky diode between 5V_EXT_IN and the 5V_EXT supply that you can pass to the Pi. This will drop around 0.4V. So you will need to provide about 5.6V from your PSU. Take care not to exceed 5.7V.

@T3P3Tony Yep, that's what I ended up doing. I spoke with Teknic support and expressed interested in the HLFB wire potentially signaling errors rather than enabled status and they filed my feature request. For now this is my solution: https://forum.duet3d.com/post/346434