poliboy

Good point. The SSD and its USB3 interface are bus powered and working standalone when booting from it. The additional USB3 HDD has a power supply attached. My expectation is,...

Thanks for your replies so far. In order to remove all doubts, I purchased a passive USB3 hub (therefore my answer took some time). The result: If I attach the...

Maybe my formulation was too complicated: I don't draw more current than the Pi can provide... Otherwise I would see the same issue with the passive hub, which is not...

Thanks for the hint. I attached this: Bottom USB3: SSD Bottom USB2: optical mouse After booting, everything was fine. Then I plugged the SSD (actively supplied) into the Top USB3....

I did another experiment, maybe this refers better to your question: Starting with Bottom USB3: SSD I booted without mouse and keyboard. Then I plugged the optical mouse into the...

I have a powered USB3 hub (combined with a HDD). If I plug this into the Pi4 instead of the passive hub, and attach the drives to the powered hub,...