[lxgr]

The Raspberry Pi 4 has a design error in its USB-C circuitry.

It does include a pull-down resistor, but wired incorrectly (compliant devices need two), which results in compliant chargers only correctly detecting it when using a “dumb” (i.e. containing no e-marker chip) USB-C-to-C cable. Your Apple cable probably has a marker (all their Macbook charging cables have one, for example).

[sidewndr46]

Thanks for the explanation. I actually found out the USB-C plug can act as a USB device. At USB 2.0 speeds oddly enough. So I have all my Pi 4s configured now in that mode and I just power them through the 5 volt header, which seems simpler. Albeit less convenient.

I had to get this USB "power blocker" that only passes the data pins through, otherwise the Pi runs off the computer it is plugged into all the time

[lxgr]

> At USB 2.0 speeds oddly enough.

That's because USB 3 is not natively provided by the SoC on the RPi 4, but rather by a dedicated IC, connected to the main SoC via PCIe :)

Hence there's two USB 3 ports and two USB 2 ports, but wired completely differently internally! Presumably the USB-C port is connected to the SoC more directly.