How did you flash the image? If I’m not mistaken, the only way to get your system image into read only memory is using
swiflash, or an over the air firmware update (with your system update concatenated into a
.spk image). If you install apps or
.update bundles over local micro USB it’s likely an overlay.
In terms of inspecting this, have a look here: https://docs.legato.io/latest/conceptsUpdates.html. You should be able to figure out what’s overlay and what’s read only by inspecting (
/mnt/flash/legato (read only) and
I’ve seen a lot of system images installed as overlays get rolled back due to some hardware failure (usually kernel driver failure). Is this by chance the behaviour you’re trying to prevent?