You just need to refresh back to the revision that’s specified in the validation set. If the channel your device is tracking still has the newer revision published, then you can use --revision to refresh to the older (valid) revision. Ex.
And actually, you don’t really need the --revision, if you re-run snap refresh $SNAP_NAME, then snapd will trigger a refresh to the revision specified in the validation-set.
Note – this currently only works for required snaps in validation sets. There’s a bug with optional snaps which is currently being worked on.
I had tried to do a “general snap refresh” but not one for a specific snap. Indeed, this reverts the snap to the one listed in the validation-set. Thanks a lot!