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:


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


Also note this is documented in the CM4 datasheet section 2.4


I rolled my own IO board for the CM4 and was convinced I'd done something wrong when the USB didn't work. I finally stumbled upon the line in the datasheet that mentions this. I kinda feel like this should be on by default....

Doesn't work in the config.txt that's in the NOOBS SD. Works with the Raspbian image though. Probably related to existence of a ...cm4...dtb file in the Raspbian FAT partition.

That was really frustrating for a while there.

Thanks.. I was wondering why I couldn't get my CM4 to USB boot.. Seems that USB needs to be enabled.. Which means the IO board can't boot from USB without having a boot partition on the SD/NVM card.

I've taken a copy of the Ubuntu 20.04 LTE boot partition on the a 500MB SD boot partition and then that boots of the Usb volume labeled writable. However it then gets stuff waiting for dev to complete so show knows what the next problem is..

Once step forwards..

In Ubuntu 20.04 image there is a line to uncoment in /boot/firmware/config.txt as explained by the comment above it.

Hello Sir, Which line I need to uncomment since the file says -> Please DO NOT modify this file; if you need to modify the boot config, the "usercfg.txt" file is the place to include user changes

Just a comment to keep someone else from falling into the same pit I did. I added this line to config.txt by connecting it via J11 and letting boot as a USB storage device. Once I could see it in Windows I edited config.txt. But no matter what the USB mouse and keyboard would never work. Finally I realized I still had power applied to J11 via the microusb cable. I recall from the schematic this flips a switch that re-routes the USB signals from the HUB and instead to J11. Unpluged from J11 and all if FINE! Only 20 minutes lost on this. :-) Not unusual for unfamiliar hardware. Lesson learned. Hope this helps someone else not waste 20 min or more.

Disable USB by default - what a stupid idea...

thanks for enlightening us JG :)