Well, I checked the DTS in the kernel: USB3-0 is set to “otg” and USB3-1 says “host”. When I edit that and set USB3-0 to “host”, lo and behold, the upper port works.
Thus I suspect that the DTS stanza to change that changes the port mode depending on rsense is missing.
Another problem: systemd-networkd is unable to bring up eth0.
Feb 14 11:11:59 TODO systemd-networkd[247]: lo: Configured
Feb 14 11:11:59 TODO systemd-networkd[247]: eth0: Could not bring up interface: Invalid argument
Feb 14 11:11:59 TODO systemd-udevd[241]: Using default interface naming scheme 'v240'.
Feb 14 11:11:59 TODO systemd-udevd[241]: link_config: autonegotiation is unset or enabled, the speed and duplex are not writable.
Feb 14 11:11:59 TODO systemd-udevd[241]: link_config: could not get ethtool features for eth0
Feb 14 11:11:59 TODO systemd-udevd[241]: Could not set offload features of eth0: Device or resource busy
Feb 14 11:11:59 TODO systemd[1]: Reached target Network.
I added /etc/systemd/system/systemd-networkd.service.d/eth0.conf
[Service]
ExecStartPre=/sbin/ip link set dev eth0 up
which fixes this but obviously is not a good long term solution.