Device tree overlays for PocketBeagle

Editing /mnt/boot/uEnv.txt_internal nor /mnt/sysroot/active/balena/overlay2/3662906acfca36b25c9f6e9fdb41a06e502e84266af4ae2c26fb93e27ff65fd3/diff/resin-boot/uEnv.txt_internal, so what file do I actually edit in a running file system?

Answering my own question…

/mnt/boot/resinOS_uEnv.txt is read by uboot, so you can set variables.
/mnt/sysroot/active/current/boot/overlays is accessible at boot time.

Hi @jkridner just checking you are all ok with this issue now? :blush:

Yep, but it would be nice to see some documentation on this.

Further, it isn’t obvious how I should be loading these files, including the overlays.

Hey Jason, I took a look at our docs and API and it seems that we don’t expose the advanced boot configurations for PocketBeagle the way we do for Raspberry Pi but it would look something like this:

Have you tried manually setting BALENA_HOST_CONFIG_dtoverlay in the Configuration panel to see if you can load different overlays via the dashboard? I don’t have the device to test with myself but this is how it works for RPi and config.txt.

If BALENA_HOST_CONFIG_dtoverlay doesn’t work as suggested then we would probably add that functionality rather than update our documentation with the workaround you found.

If you need a custom overlay that isn’t present in balenaOS at all, we usually recommend you test with the method you are currently using then PR it on GitHub - balena-os/balena-beaglebone: Balena support for Beaglebone boards so we can add it to future releases!

BALENA_HOST_CONFIG_dtoverlay doesn’t work. Tried on balenaCloud v16.2.3 + BeagleBone Black running balenaOS 2.107.35.

FWIW, I tried setting overlays in three places:

  1. BALENA_HOST_CONFIG_dtoverlay
  2. /boot/uEnv.txt
  3. /mnt/boot/uEnv.txt

Only #3 seems to work. Other sources online refer to #2. Confusingly both /boot and /mnt/boot exist on balenaOS, but only /mnt/boot/uEnv.txt works.

@klutchell This would be really useful. How could we request this?

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