For instace dropbear (ssh server) settings are in /etc/default/dropbear file. File has root-only access. So after reflash I have to 1) restore backup 2) install dropbear-server 3) install xterm 4) run xterm and chmod /etc/default/dropbear so user can write there 5) restore backup again.
If I can run osso-backup as root - there will be just 1) restore backup 2) install apps