corrupted reference store after powercut

[robertgzr]

May 11 14:49:08 51f90cb balenad[23254]: time="2021-05-11T14:49:08.870073221Z" level=error msg="layer does not exist, not restoring image sha256:f7942a26d161ae2"
May 11 14:49:08 51f90cb balenad[23254]: time="2021-05-11T14:49:08.873468548Z" level=info msg="stopping event stream following graceful shutdown" error="contexty
May 11 14:49:08 51f90cb balenad[23254]: time="2021-05-11T14:49:08.873626743Z" level=info msg="stopping healthcheck following graceful shutdown" module=libcontad
May 11 14:49:09 51f90cb balenad[23254]: Error starting daemon: Couldn't create reference store repository: invalid character 's' looking for beginning of value
May 11 14:49:09 51f90cb systemd[1]: balena.service: Main process exited, code=exited, status=1/FAILURE
May 11 14:49:09 51f90cb systemd[1]: balena.service: Failed with result 'exit-code'.
May 11 14:49:09 51f90cb systemd[1]: Failed to start Balena Application Container Engine.
May 11 14:49:10 51f90cb systemd[1]: balena.service: Service hold-off time over, scheduling restart.
May 11 14:49:10 51f90cb systemd[1]: balena.service: Scheduled restart job, restart counter is at 12.
May 11 14:49:10 51f90cb systemd[1]: Stopped Balena Application Container Engine.
May 11 14:49:10 51f90cb systemd[1]: Closed Docker Socket for the API.
May 11 14:49:10 51f90cb systemd[1]: Stopping Docker Socket for the API.
May 11 14:49:10 51f90cb systemd[1]: Starting Docker Socket for the API.
May 11 14:49:10 51f90cb systemd[1]: Listening on Docker Socket for the API.
May 11 14:49:10 51f90cb systemd[1]: Starting Balena Application Container Engine...

The error originates here:

balena-engine/daemon/daemon.go

Lines 1071 to 1075 in b6b8d35

	refStoreLocation := filepath.Join(imageRoot, `repositories.json`)
	rs, err := refstore.NewReferenceStore(refStoreLocation)
	if err != nil {
	return nil, fmt.Errorf("Couldn't create reference store repository: %s", err)
	}

/var/lib/docker/overlay/repositories.json contained:

sha256:e94321879d0937e050448936ff3d9ea3b82278bf94466f317b45fdbb086e5f02

a working device had:

{
  "Repositories": {
    "balena/amd64-supervisor": {
      "balena/amd64-supervisor:v9.15.7": "sha256:f7942a26d161ae219177452f024433fd2432d89dcb1cfdc96433e26190f35610",
      "balena/amd64-supervisor@sha256:d619a83ac10f65906dc268abb151b6df5085ad9ec72c91f920acf0ba9bfc47bf": "sha256:f7942a26d161ae219177452f024433fd2432d89dcb1cfdc96433e26190"
    }
  }
}