USB 2.0 ports not working on the Compute Module 4? Check your overlays!

Out of the box, to conserve power, the new Raspberry Pi Compute Module 4 doesn't enable its built-in USB 2.0 ports.

Compute Module 4 IO Board USB 2.0 ports are disabled by default

You might notice that if you plug something into one of the USB 2 ports on the IO Board and don't see it using lsusb -t. In fact, you see nothing, by default, if you run lsusb -t.

To enable the USB 2.0 ports on the Compute Module 4, you need to edit the boot config file (/boot/config.txt) and add:

dtoverlay=dwc2,dr_mode=host

Then reboot the Pi. Now you should be able to use the built-in USB 2.0 ports!

Comments

Also note this is documented in the CM4 datasheet section 2.4

:)