Hello, I have came across the issue today. I flashed the emlid os (version 20200922) on the sd card and booted on a Pi 4 8gb. Everything works fine unless I upgrade it with sudo apt-get update && sudo apt-get upgrade. I found that the usb ports are dead after the device is rebooted.
I can connect it via ssh. Also i found it when i change the keyboard layout in raspi-config, it shows “cat: ‘/sys/bus/usb/devices/:/bInterfaceClass’: No such file or directory” ,and also 2 more errors.
I tested it again with a clean raspbian lite os, it works fine after upgrading. I also own a Pi 3 4gb, it works fine with emlid os and upgrading. This issue happens to my new Pi 4 8gb.
Pi model 4B 8GB Ram, 64GB sd card, official power supply.
1 March, 2021