Edit Config.txt using RPi CM4

Hi all,

So it seems that USB port is disabled by default in RPi CM4. How can we mount boot partition HA OS?

CM4 does not have same disk structure as an SD card on a regular Pi 4

A CM4 doesn’t have USB ports nor a SD card port. Heck, the lite version doesn’t even have storage.
Which of the CM4 version do you have, and which I/O board?

Hi Chris,

You are right about this. I use the official IO board: https://www.raspberrypi.org/products/compute-module-4-io-board/ + CM4 SC0277 (2gb mem, 16gb flash and wifi)

Ok. So your question is actually “How to I mount /boot on HassOS so as to edit config.txt, so to enable USB”, right?

Check

Hi Chris,

Well, you could phrase it like that. End result would be the same, access to config.txt.

It seems that i am accessing “addon SSH”, not “host SSH”, i do not have the correct permissions to mount the drive. (my root access to ssh was not really root at all…).

According to this page; Debugging the Home Assistant Operating System | Home Assistant Developer Docs we need to add key using USB device… Would that be possible since USB is deactivated? Or does it initiate USB while booting?

Use :

2 Likes

Hi Francis,

Perfect. That would probably to the trick, as an alternative method of accessing config.txt:

  • Turn off CM4 IO Board
  • Place jumper on “disable eMMC boot”
  • Attach CM4 to your computer and launch rpiboot
  • One of the partitions that now are accessible is the boot partition. Here you can edit config.txt as you wish.
  • Once changes as done, unmount the drive and remove CM4 from your computer.
  • Remove jumper on “disable eMMC boot”
  • Turn CM4 back on. I now have USB access atleast :slight_smile:

And to enable USB, add following in the bottom of your config.txt file:

dtoverlay=dwc2,dr_mode=host

I do this method and all I get is partition needs formatted

On my IO board, the entire EMMC is made accessible, but partitions cannot be mounted presumably due to the way the EMMC is formatted, Thus, no boot access.

I am trying to get my usb enabled as well. I understand I need to edit the config.txt. But where is it??? I run the rpiboot, then install the image. After that, 4 “drives” show up and I can access them via the gui (i’m on linux) or the command line. But I can’t find any config.txt anywhere. I can find a boot directory a few levels down on one of the mounts, but no files in there. I tried adding my own config.txt with the line noted, but it is not a writeable directory.

Can anyone give a detailed step by step showing where this config.txt file is located?

image

Where is the config file here?

Thanks,

Alan