Ok now I see something, looks good now 
, but it wasn’t work before I flashed the medkit.
root@turris:~# btrfs scrub start -B /
scrub done for c504320d-85c8-4fab-9bd0-8a00bfea9cd2
scrub started at Tue Sep 19 15:15:40 2017 and finished after 00:00:07
total bytes scrubbed: 302.82MiB with 0 errors