Hi @kimmy
I am sorry for your observed issue.
Those ports on the Microhard design are USB2 rated at 500mA and meet USB2 specs of 5V +/- 10%, which allows for 4.5V and still be considered in-spec.
You are not the first to hit USB2 power delivery limitations.
If your system really requires that precise of a voltage, and less of an allowance to the drop, you may need to consider pulling power directly off of our Power Module 5V, and not VBUS. Many of our solutions that require higher power than USB can handle do this, and many of our newer boards have new circuits that provide more than 500mA on VBUS to help with these higher demanding use cases.
If you want to explore that type of test, you can use this board which has a jumper option to bypass VBUS and instead provide the 5V power supply voltage to the USB connector:
https://docs.modalai.com/usb-epxansion-with-fastboot-v2-datasheet/
That will provide a good test for you to ensure your system operates the way you need before committing to a custom wire harness.
Let me know if that helps!