Can't initialize on Raspberry Pi Compute Module 4

[Hadmut Danisch]

Hi,

I recently tried to install Ubuntu Core 22 on a Raspberry Pi Compute Module 4, plugged into a board, which does not have USB3-Ports, because it uses the one and only PCIe-Bus for NVMe-Storage, and just has the USB2-Ports.

Problem: When booting Ubuntu Core for the first time, it requires to enter the ID of a launchpad account to download the ssh public key, otherwise there is no way to login.

But in contrast to a regular Raspberry Pi, the compute module starts with USB2-Ports disabled, so no keyboard works.

Allegedly, there are boot options to enable, e.g.

https://www.jeffgeerling.com/blog/2020/usb-20-ports-not-working-on-compute-module-4-check-your-overlays

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

However, I found only one config.txt, and modifying it didn't help.

My hope was, that once Ubuntu Core 22 is available for rpi-imager, making use of the init_format entry to allow the imager to preconfigure an account, like for Ubuntu Server or Raspberry OS, but Ubuntu Core does not offer such an option.

So what is the recommended procedure to launch Ubuntu Core 22 on a Raspberry Pi Compute Module 4, if plugged into a board without USB3 ports, thus with disabled USB2 ports only?

It should either be possible to preconfigure an account, i.e. to not need keyboard and usb for getting functional, or to enable the usb2 ports and use a keyboard.