Booting the raspberry pi4 4G works just fine using a usb drive to boot on but the raspberry pi4 8G board will not boot the mainline kernel.

I have seen this issue in the past using the Pi Foundation kernel and they said that the issue was with the board revisions. Using the Pi Foundation now has working usb ports. The pi4 4G and the pre production pi4 8G had the same revision but the revision changed on the pi4 8G production boards.