synology> which bash
synology> which sh
/bin/sh
synology> which ash
/bin/ash
synology> ls -l /bin/sh
lrwxrwxrwx 1 root root 7 Jun 5 11:27 /bin/sh -> busybox
synology> ls -l /bin/ash
lrwxrwxrwx 1 root root 7 Jun 5 11:27 /bin/ash -> busybox
Not really fair to blame the plane in that case.