zlacker

I can't tell if the USB port that usually delivers power is the only one that supports "USB Device Mode" (USB OTG). Can someone confirm? If I could use any port, then there would be no need for powering the pi with a serial USB adapter.

>>ed2551+(OP)
From memory, this is correct. It's only the USB-C port that allows OTG operation. I remember a while back seeing someone selling a special splitter cable for the rpi4 which provided 2 separate USB connectors, one for powering the rpi and one for attaching the pi as a gadget to a USB host port. But I can't remember where I saw it, and haven't been able to turn up a link to it.