@tomp, @stgraber – big thanks for your time spent digging in to this one, and for the detailed writeup. Understood you won’t be able to fix the custom kernel issue.
Is running in privileged mode a reasonable workaround for this issue or are other dragons lurking (at least from what you’ve seen – I know you can’t answer that question with 100% certainty)?
If so, I’ll take this back to the snapcraft discourse to work through the next round of issues with snapcraft --use-lxd
with privileged containers.