Usb sometime doesn't work after boot up

customer design their own carrier board, the usb ports connect with usb hub, 4G module and wifi module. most time the system works, sometime they hit with USB doesn’t work at tegra boot stage and didn’t probe all the usb device after booting into the system. there are following error message:
0004.470] uhub0: 9 ports with 9 removable, self powered
[0013.800] get polling status timeout.

Just speculating, but if this works and only sometimes fails, then probably there is a signal quality issue. Signal quality is in part determined by trace layout, but can also change based on environmental noise. Sensitivity to this can change with temperature. I don’t know if you have any method of experimenting with extra ground plane shielding around any traces related to this, but if you do, then give it a shot. In particular, if the HUB is connected to 4G, then perhaps the RF from the 4G is adding to environmental noise (and even slight differences in antenna placement or surrounding environment can drastically change when the Jetson sees).

Note that power delivery can also be subject to part of the noise issue, especially if the 4G is near the power delivery.